Synthesis of novel europium-labeled estradiol derivatives for time-resolved fluoroimmunoassays.

The O-(5-carboxypentyl)-, O-(4-aminobutyl)-, O-(6-aminohexyl)oximes of 2- and 4-formylestradiol as well as the 4-carboxyethylthioether derivative of estradiol were synthesized. These estradiol derivatives were characterized using IR-, 1H-, and 13C NMR spectroscopy. All synthesized estradiol derivatives were labeled with europium chelates. These "tracers" were purified and tested in a competitive time-resolved fluoroimmunoassay with monoclonal antibody (SSI 57-2) raised against the 6-O-(carboxymethyl)oxime-bovine serum albumin derivative of estradiol. All the tested europium-labeled estradiol-4-derivatives were bound by the antibody, whereas tracers linked via position 2 were not recognized by this antibody. It was observed that tracers conjugated via C-4 gave more sensitive standard curves than tracers conjugated via C-6. Especially, the estradiol-4-thioether derivative was found to be highly useful in time-resolved fluoroimmunoassays of estradiol while using this antibody.     

Synthesis of immunoreagents for detection of deoxypyrrololine, a cross-link of bone collagen

Two immunogens (5,6) and two probes (fluorescent 7 and chemiluminescent 8) were prepared from benzyl ester (-)-10. These immunoreagents (5,6 and 7,8) are useful for detection of collagen cross-link (+)-deoxypyrrololine (Dpl, 4), and for development of assays for osteoporosis.     

New synthesis of (S)-dimethyl-4,4'-dimethoxy-5,6,5',6'-dimethenedioxy-biphenyl-2,2'-dicarboxylate by configuration transform

(R/S)-4,4'-Dimethoxy-5,6,5',6'-dimethenedioxy-2,2'-di-(4(S)-methyl-oxazoline-1)-biphenyl has been synthesized from dimethyl-4,4'-dimethoxy-5,6,5',6'-dimethenedioxy-biphenyl-2,2'-dicarboxylate, and then the diastereoisomer mixture was almost fully converted to a single diastereoisomer with S-configuration ((S)-3) through the key configuration transform promoted by CuI, which was confirmed by CD, HPLC and (13)C NMR. The C(2)-symmetric biphenyl, (S)-dimethyl-4,4'-dimethoxy-5,6,5',6'-dimethenedioxy-biphenyl-2,2'-dicarboxylate was prepared easily via the hydrolysis and ester exchange of (S)-3.     

The usefulness of bone metabolic indices for the prediction of changes in bone mineral density after parathyroidectomy in patients with primary hyperparathyroidism.

Patients with primary hyperparathyroidism (pHPT) have reduced bone mineral density (BMD). Although pHPT causes high bone turnover, the exact metabolic bone markers useful for predicting changes in BMD after parathyroidectomy (PTX) remain elusive. The present study was performed to examine the relationship between bone metabolic indices and BMD changes after PTX in 29 pHPT Japanese patients, which received PTX successfully. BMD values were measured by dual-energy X-ray absorptiometry in the lumbar spine and distal one third of radius. As for bone metabolic indices, serum bone-type alkaline phosphates (BAP), serum osteocalcin (OCN), urinary deoxypiridinoline (Dpd), and urinary type I collagen cross-linked N-telopeptides (NTX) were measured. The study included 10 male and 19 female patients (17 postmenopausal). Urinary Dpd, but not NTX was significantly correlated with serum BAP and OCN. Either bone formation or bone resorption indices were significantly and highly correlated with Z-score of BMD in the radius, but not at lumbar spine. Urinary Dpd was significantly correlated with BMD changes at both lumbar spine and radius and at all time points over the two years after PTX. These correlations were most potent among bone metabolic indices in this study. The measurement of urinary Dpd would be useful for predicting long-term changes in BMD at radial and lumbar spine after PTX than other bone metabolic indices.     

Kinetic analysis of matrix metalloproteinase activity using fluorogenic triple-helical substrates

Matrix metalloproteinase (MMP) family members are involved in the physiological remodeling of tissues and embryonic development as well as pathological destruction of extracellular matrix components. To study the mechanisms of MMP action on collagenous substrates, we have constructed homotrimeric, fluorogenic triple-helical peptide (THP) models of the MMP-1 cleavage site in type II collagen. The substrates were designed to incorporate the fluorophore/quencher pair of (7-methoxycoumarin-4-yl)acetyl (Mca) and N-2,4-dinitrophenyl (Dnp) in the P(5) and P(5)' positions, respectively. In addition, Arg was incorporated in the P(2)' and P(8)' positions to enhance enzyme activity and improve substrate solubility. The desired sequences were Gly-Pro-Lys(Mca)-Gly-Pro-Gln-Gly approximately Leu-Arg-Gly-Gln-Lys(Dnp)-Gly-Ile/Val-Arg. Two fluorogenic substrates were prepared, one using a covalent branching protocol (fTHP-1) and one using a peptide self-assembly approach (fTHP-3). An analogous single-stranded substrate (fSSP-3) was also synthesized. Both THPs were hydrolyzed by MMP-1 at the Gly approximately Leu bond, analogous to the bond cleaved in the native collagen. The individual kinetic parameters for MMP-1 hydrolysis of fTHP-3 were k(cat) = 0.080 s(-1) and K(M) = 61.2 microM. Subsequent investigations showed fTHP-3 hydrolysis by MMP-2, MMP-3, MMP-13, a C-terminal domain-deleted MMP-1 [MMP-1(Delta(243-450))], and a C-terminal domain-deleted MMP-3 [MMP-3(Delta(248-460))]. The order of k(cat)/K(M) values was MMP-13 > MMP-1 approximately MMP-1(Delta(243-450)) approximately MMP-2 > MMP-3 approximately MMP-3(Delta(248-460)). Studies on the effect of temperature on fTHP-3 and fSSP-3 hydrolysis by MMP-1 showed that the activation energies between these two substrates differed by 3.4-fold, similar to the difference in activation energies for MMP-1 hydrolysis of type I collagen and gelatin. This indicates that fluorogenic triple-helical substrates mimic the behavior of the native collagen substrate and may be useful for the investigation of collagenase triple-helical activity.     

Synthesis and structure determination of some sugar amino acids related to alanine and 6-deoxymannojirimycin.

(5'R)-5'-Methyl-5'-[methyl (4S)-2,3-O-isopropylidene-beta-L-erythrofuranosid-4-C-yl]-imidazolidin-2',4'-dione was synthesised starting from methyl 6-deoxy-2,3-O-isopropylidene-alpha-D-lyxo-hexofuranosid-5-ulose applying the Bucherer-Bergs reaction. Its 5'-R configuration was confirmed by X-ray crystallography. Corresponding alpha-amino acid-methyl (5R)-5-amino-5-C-carboxy-5,6-dideoxy-alpha-D-lyxo-hexofuranoside (alternative name: 2-[methyl (4S)-2,3-O-isopropylidene-beta-L-erythrofuranosid-4-C-yl]-D-alanine) was obtained from the above hydantoin by acid hydrolysis of the isopropylidene group followed by basic hydrolysis of the hydantoin ring. Total deprotection afforded 5-C-carboxy-6-deoxymannojirimycin. Analogously, methyl (5S)-5-amino-5-C-carboxy-5,6-dideoxy-alpha-L-lyxo-hexofuranoside and 5-C-carboxy-6-deoxy-L-mannojirimycin were prepared from the corresponding (5'S)-5'-methyl-5'-[methyl (4R)-2,3-O-isopropylidene-beta-D-erythrofuranosid-4-C-yl]-imidazolidin-2',4'-dione starting from methyl 6-deoxy-2,3-O-isopropylidene-alpha-L-lyxo-hexofuranosid-5-ulose.     

Syntheses of stable isotope-labeled 6 beta-hydroxycortisol, 6 beta-hydroxycortisone,and 6 beta-hydroxytestosterone

A method is described for the preparation of two types of multi-labeled 6 beta-hydroxycortisol containing either five deuterium atoms at C-19 methyl and C-1 methylene or four 13C atoms at C-1, C-2, C-4, and C-19 in addition to the five deuterium atoms for use as analytical internal standards for gas chromatography-mass spectrometry (GC-MS). BMD derivatives of [1,1,19,19,19-2H(5)]cortisone and [1,2,4,19-13C(4),1,1,19,19,19-2H(5)]cortisone (cortisone-2H(5)-BMD and cortisone-13C(4),2H(5)-BMD) were first synthesized via indan synthon method starting from optical active 11-oxoindanylpropionic acid and labeled isopropenyl anion ([1,1,3,3,3-2H(5)]- or [1,3-13C(2),1,1,3,3,3-2H(5)]isopropenyl anion). The labeled isopropenyl anion was prepared from commercially available [1,1,1,3,3,3-2H(6)]- or [1,3-13C(2),1,1,1,3,3,3-2H(6)]acetone. Ultraviolet (UV) irradiated autoxidation at C-6 position of 3-ethyl-3,5-dienol ether derivatives of the labeled cortisone-BMDs gave 6 beta-hydroxy-[1,1,19,19,19-2H(5)]cortisone-BMD and 6 beta-hydroxy-[1,2,4,19-13C(4),1,1,19,19,19-2H(5)]cortisone-BMD, respectively, as a mixture of 6 beta- and 6 alpha-epimers in a ratio of 4:1. Separation of 6 beta- and 6 alpha-epimers by thin-layer chromatography (TLC) and subsequent hydrolysis of the BMD group at C-17 gave pure labeled 6 beta-hydroxycortisone. After protecting the keto group at C-3 of the labeled 6 beta-hydroxycortisone-BMD as semicarbazone, reduction of 11-keto group with NaBH(4) and subsequent removal of the C-3 and C-17 protecting groups gave 6beta-hydroxy-[1,1,19,19,19-2H(5)]cortisol (6 beta-hydroxycortisol-2H(5)) and 6 beta-hydroxy-[1,2,4,19-13C(4),1,1,19,19,19-2H(5)]cortisol (6 beta-hydroxycortisol-13C(4),2H(5)), respectively, as a mixture of 6 beta- and 6 alpha-epimers (6 beta:6 alpha=4.4:1). The isotopic compositions of 6 beta-hydroxycortisol-2H(5) and 6 beta-hydroxycortisol-13C(4),2H(5) were 90.9 and 92.1 at.%, respectively. Furthermore, 6 beta-hydroxy-[1 alpha,16,16,17 alpha-2H(4)]testosterone was synthesized by the UV irradiated autoxidation at C-6 position of 3-ethyl-3,5-dienol ether derivative of deuterium-labeled testosterone ([1 alpha,16,16,17 alpha-2H(4)]testosterone) obtained by using catalytic deuteration and hydrogen-deuterium exchange reactions.     

Synthesis of (-)-methyl shikimate via enzymatic resolution of (1S*, 4R*, 5R*)-4-hydroxy-6-oxabicyclo[3.2.1]oct-2-en-7-one.

The synthesis of methyl (-)-shikimate [(-)-2] was achieved via lipase-catalyzed optical resolution of (1S*, 4R*, 5R*)-4-hydroxy-6-oxabicyclo[3.2.1]oct-2-en-7-one (3). Transesterification of (+/-)-3 and vinyl acetate with lipase MY and subsequent hydrolysis gave optically pure (-)-3. This compound was converted to (-)-2 in two steps.     

Determination of the epimeric composition of ibuprofenyl-CoA

Ibuprofen [racemic2-(4-isobutylphenyl)propionic acid] is a 2-arylpropionic acid nonsteroidal anti-inflammatory drug which undergoes unidirectional, R to S chiral inversion in vivo. It has been proposed that this chiral inversion phenomenon occurs via a coenzyme A (CoA) thioester intermediate. To characterize the formation and metabolism of this metabolic intermediate, ibuprofenyl-CoA, reference standards were needed and thus the CoA derivatives of (R)-, (S)-, and racemic ibuprofen were chemically synthesized. An HPLC assay employing a C18 reverse-phase column was developed to quantitate "total" ibuprofenyl CoA. Samples collected from this assay were then analyzed for ibuprofenyl-CoA epimeric composition by chiral chromatography employing a Chiral-AGP alpha 1-acid glycoprotein column. The applicability of these methods was demonstrated by assessing (R)- and (S)-ibuprofenyl-CoA hydrolysis and epimerization following incubation with rat liver homogenates. Rat liver homogenate catalyzed the complete and rapid epimerization of ibuprofenyl-CoA and the rate constants for (R)- and (S)-ibuprofenyl-CoA hydrolysis were equal. ATP and CoA were found to inhibit rat liver-catalyzed ibuprofenyl-CoA hydrolysis by 70-80% with no effect on epimerization. Additionally, it was demonstrated that traditional indirect ibuprofenyl-CoA assays which employ basic hydrolysis result in erroneous epimeric ratio determinations due to chemical epimerization.     

Enhanced cleavage of diaminopimelate-containing isopeptides by leucine aminopeptidase and matrix metalloproteinases in tumors: application to bioadhesive peptides.

We prepared (2S,6S)-Z-Dpm(Z)(OMe) (4) by protease-mediated hydrolysis of (R,R/S,S)-Z-Dpm(Z)(OMe)-OMe (3), converted it to (2S,6S)-Dpm(Z)(OMe) (6) via PCI5 to an NCA intermediate and hydrolysis, protected the amino group with Boc to give (2S,6S)-Boc-Dpm(Z)(OMe) (7), which upon ammonolysis of the Me ester afforded (2S,6S)-Boc-Dpm(Z)(NH2) (8). Hydrogenolysis of 8 and protection with Fmoc gave (2S,6S)-Boc-Dpm(Fmoc)(NH2)(10). Using 10 and SPPS, we prepared three Dpm-containing peptides and their corresponding Lys peptides. Enzymatic studies with mLAP and cLAP showed that the Leu moiety in Ac-Gly-(2S,6S)-Dpm(Leu)(NH2)-Ala (14) was hydrolyzed 68-fold and >1000-fold more rapidly, respectively, than that in Ac-Gly-Lys(Leu)-Ala (12). The enhanced rate of Leu formation from 14 compared to 12 was also observed with homogenates of mouse C3 sarcomas. This homogenate also hydrolyzed Ac-Gly-(2S,6S)-Dpm(Ac-Gly-Pro-Gln-Gly-Leu)(NH2)-Ala (16) to Ac-Gly-(2S,6S)-Dpm(NH2)-Ala (13), Leu and Ac-Gly-Pro-Gln-Gly (17). This implies the side chain is cleaved first by endopeptidases, such as matrix metalloproteinases (MMPs), and then the remaining Leu is cleaved by LAP-like exopeptidases. The rate of liberation of 17 from 16 and the corresponding Lys isopeptide, Ac-Gly-Lys(Ac-Gly-Pro-Gln-Gly-Leu)-Ala (15), was not significantly different. The rate of formation of 13 was faster from 16 than Ac-Gly-Lys-Ala (11) was from 15. Thus, the entire isopeptide side chain can be removed by the cooperative action of LAP-like and MMP-like peptidases present in tumor tissue, which occurs faster in the Dpm peptide 16 than in the Lys peptide 15. The rate of formation of 13 from 16 by lung, liver, and intestine homogenates (from the same C3 tumor-bearing mice) was comparable to or higher than from the tumor homogenates, but the rate by blood was only 4% the value of the tumor homogenates. Analogs of a bioadhesive fragment from the laminin alpha1 chain were prepared by replacing the essential Lys with Dpm(NH2) (20) and Dpm(Leu)(NH2) (21). Both Dpm-containing peptides were active, although considerably weaker than the corresponding Lys peptides 18 and 19, in a cell attachment assay with human fibrosarcoma HT-1080 cells.     

5'-Fluoro-5'-deoxyaristeromycin

5'-Fluoro-5'-deoxyaristeromycin (2) has been prepared via a Mitsunobu coupling of (1S,2S,3R,4S)-2,3-(cyclopentylidenedioxy)-4-fluoromethylcyclopentan-1-ol with N6-bis-boc protected adenine. This procedure is adaptable to preparing a number of 5'-fluoro-5'-deoxycarbocyclic nucleoside analogs with diversity in the heterocyclic base. Antiviral analysis found promising activity for 2 toward measles but no other viruses. No cytotoxicity was observed for 2.     

Ligation of integrin alpha 3beta 1 by laminin 5 at the wound edge activates Rho-dependent adhesion of leading keratinocytes on collagen

Wounding of the epidermis signals the transition of keratinocytes from quiescent anchorage on endogenous basement membrane laminin 5 to migration on exposed dermal collagen. In this study, we attempt to characterize activation signals that transform quiescent keratinocytes into migratory leading cells at the wound edge. Previously, we reported that adhesion and spreading on collagen via integrin alpha(2)beta(1) by cultured human foreskin keratinocytes (HFKs) requires RhoGTP, a regulator of actin stress fibers. In contrast, adhesion and spreading on laminin 5 requires integrins alpha(3)beta(1) and alpha(6)beta(4) and is dependent on phosphoinositide 3-hydroxykinase (Nguyen, B. P., Gil, S. G., and Carter, W. G. (2000) J. Biol. Chem. 275, 31896-31907). Here, we report that quiescent HFKs do not adhere to collagen but adhere and spread on laminin 5. By using collagen adhesion as one criterion for conversion to a "leading wound cell," we found that activation of collagen adhesion requires elevation of RhoGTP. Adhesion of quiescent HFKs to laminin 5 via integrin alpha(3)beta(1) and alpha(6)beta(4) is sufficient to increase levels of RhoGTP required for adhesion and spreading on collagen. Consistently, adhesion of quiescent HFKs to laminin 5, but not collagen, also promotes expression of the precursor form of laminin 5, a characteristic of leading keratinocytes in the epidermal outgrowth. We suggest that wounding of quiescent epidermis initiates adhesion and spreading of keratinocytes at the wound edge on endogenous basement membrane laminin 5 via alpha(3)beta(1) and alpha(6)beta(4) in a Rho-independent mechanism. Spreading on endogenous laminin 5 via alpha(3)beta(1) is necessary but not sufficient to elevate expression of precursor laminin 5 and RhoGTP, allowing for subsequent collagen adhesion via alpha(2)beta(1), all characteristics of leading keratinocytes in the epidermal outgrowth.     

Covalent structure of collagen. Amino acid sequence of an arthritogenic cyanogen bromide peptide from type II collagen of bovine cartilage

Bovine articular type II collagen was prepared by limited pepsin digestion, differential salt fractionation and carboxymethylcellulose chromatography. Cyanogen bromide digestion of purified type II collagen alpha chains yielded twelve distinct peptides designated CB1-12. The peptide alpha 1(II)-CB11 was isolated by carboxymethylcellulose chromatography and Sephadex G-75S gel filtration. Automated Edman degradation together with chymotrypsin, thermolysin and trypsin digestion enabled identification of its complete amino acid sequence. Compared with type I and type III collagen, the data show similarity with alpha 1(I)-CB8 and alpha 1(III)-CB6-1-8-10-2 peptides, respectively. The peptide is located within residues 124-402 of the alpha 1(II) collagen chain and with its identification, now extends the known amino acid sequence of bovine type II cartilage collagen to 660 amino acid residues including alpha 1(II)-CB1-2-6-12-11-8-10 (partial). This corresponds to alpha 1(I)-CB0-1-2-4-5-8-3-7 (partial; 1-660) and alpha 1(III)-CB3A-3B-3C-7-6-1-8-10-2-4-5 (partial; 1-660) of bovine alpha 1(I) and alpha 1(III) collagen chains.     

Formation pathways for lysine-arginine cross-links derived from hexoses and pentoses by Maillard processes: unraveling the structure of a pentosidine precursor

Covalently cross-linked proteins are among the major modifications caused by the advanced Maillard reaction. So far, the chemical nature of these aggregates and their formation pathways are largely unknown. Synthesis and unequivocal structural characterization are reported for the lysine-arginine cross-links N(6)-(2-([(4S)-4-ammonio-5-oxido-5-oxopentyl]amino)-5-[(2S,3R)-2,3,4- trihydroxybutyl]-3,5-dihydro-4H-imidazol-4-ylidene)-l-lysinate (DOGDIC 12), N(6)-(2-([(4S)-4-ammonio-5-oxido-5-oxopentyl]amino)-5-[(2S)-2,3-dihydroxypropyl]-3,5-dihydro-4H-imidazol-4-ylidene)-l-lysinate (DOPDIC 13), and 6-((6S)-2-([(4S)-4-ammonio-5-oxido-5-oxopentyl] amino)-6-hydroxy-5,6,7,7a-tetrahydro-4H-imidazo[4,5-b] pyridin-4-yl)-l-norleucinate (pentosinane 10). For these compounds, as well as for glucosepane 9 and pentosidine 11, the formation pathways could be established by starting from native carbohydrates, Amadori products, and 3-deoxyosones, respectively. Pentosinane 10 was unequivocally proven to be an important precursor of pentosidine 11, which is a well established fluorescent indicator for advanced glycation processes in vivo. The Amadori products are shown to be the pivots in the formation of the various cross-links 9-13. The bicyclic structures 9-11 are directly derived from aminoketoses, whereas 12 and 13 stem from reaction with the 3-deoxyosones. All products 9-13 were identified and quantified from incubations of bovine serum albumin with the respective 3-deoxyosone or carbohydrate. From these results it seems fully justified to expect both glucosepane 9 and DOGDIC 12 to constitute important in vivo cross-links.     

Some non-anomerically C-C-linked carbohydrate amino acids related to leucine-synthesis and structure determination

(5'R)-5'-Isobutyl-5'-[methyl (4R)-2,3-O-isopropylidene-beta-L-erythrofuranosid-4-C-yl]-imidazolidin-2',4'-dione was synthesised starting from methyl 2,3-O-isopropylidene-alpha-D-lyxo-pentodialdo-1,4-furanoside via methyl 6-deoxy-6-isopropyl-2,3-O-isopropylidene-alpha-D-lyxo-hexofuranosid-5-ulose applying the Bucherer-Bergs reaction. Its 5'-R configuration was confirmed by X-ray crystallography. Corresponding alpha-amino acid-methyl (5R)-5-amino-5-C-carboxy-5,6-dideoxy-6-isopropyl-alpha-D-lyxo-hexofuranoside (alternative name: 2-[methyl (4R)-beta-L-erythrofuranosid-4-C-yl]-D-leucine) was obtained from the above hydantoin by acid hydrolysis of the isopropylidene group followed by basic hydrolysis of the hydantoin ring. Analogous derivatives with 5S configuration, formed in a minority, were also isolated and characterised.     

Synthesis of cerebroside, lactosyl ceramide, and ganglioside GM3 analogs containing beta-thioglycosidically linked ceramide

Coupling of the sodium salt of 2,3,4,6-tetra-O-acetyl-1-thio-beta-D-glucopyranose, -beta-D-galactopyranose, O-(2,3,4,6-tetra-O-acetyl-beta-D-galactopyranosyl)-(1----4)-2,3,6-tri-O- acetyl- 1-thio-beta-D-glucopyranose, or O-(methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D-glycero-alpha-D-galacto -2- nonulopyranosylonate)-(2----3)-O-(2,3-di-O-acetyl-6-O-bezoyl -beta-D- galactopyranosyl)-(1----4)-3-O-acetyl-2,6-di-O-benzoyl-1-thio-beta-D- glucopyranose, which were prepared from the corresponding 1-S-acetates, 1, 3, 6, and 9, with (2S,3R,4E)-2-azido-3-O-benzoyl-1-O-(p-tolylsulfonyl)-4-oc tadecene-1,3-diol (12) derived by tosylation of 11, gave the corresponding beta-thioglycosides 13, 17, 21, and 25, respectively in good yield. The beta-thioglycosides obtained were converted, via selective reduction of the azide group, condensation with octadecanoic acid, and removal of the protecting groups, into the title compounds.     

Some ring-opening reactions of a diepoxide derived from (−)-quinic acid

A useful preparative route to nitrogen-containing, carbocyclic derivatives is described from (−)-quinic acid. (−)-Quinic acid was converted via the 3,4-O-cyclohexylidene-lactone into 1- -3-O-tosyl-5-C-tosyloxymethylcyclohexane-1,2,5/3-tetrol (5) by sequential reduction with sodium borohydride, toluene-p-sulphonylation, and acid hydrolysis. Reaction of the disulphonate 5 with methanolic sodium methoxide afforded 1- -1,2:5,7-dianhydro-5-C-hydroxymethylcyclohexane-1,2,3,5/0-tetrol (6). The ring-opening reactions of the diepoxide 6 with azide ion furnished a mixture of two diazides 9 and 13 in the ratio 4 to 1. The structure and conformation of the derived dibenzoates 10 and 14 have been determined by n.m.r. spectroscopy.     

Synthesis of C-6 Pyrimidine Acyclic Nucleoside Analogs as Potential Antiviral Agents

Abstract

A number of pyrimidine acyclic nucleosides in which the acyclic moiety is attached to the C-6 position rather than N-1 of the pyrimidine ring have been prepared. This was accomplished via treatment of lithiated 2,4-dimethoxy-5,6-dimethylpyrimidine, or, 2,4-dimethoxy-6-methylpyrirnidine with 1,3-bis-(benzyloxy)-2-propanone, benzyl chloromethyl ether or oxirane, respectively, to give the corresponding key intermediates 6-[3-benzyloxy-2-[(benzyloxy)methyl]-2-hydroxypropyl]-2,4-dimethoxy-5-methylpyrimidine (2a), 6-[3-Denzyloxy-2-[(benzyloxy)methyl]-2-hydroxypropyl]-2,4-dimethoxypyrimidine(2b), 6-(2-benzyloxyethyl)-2,4-dimethoxy-5-methylpyrimidine (3), and2,4-dunethoxy-6-(3-hydroxypropyl)-5-methylpyrimidine (4a). After acidic hydrolysis, followed by debenzylation with boron trichloride these key intermediates were converted to the target C-6 pyrimidine acyclic derivatives. Compounds 6–8b, 11–13, 15, 16, 20, 22, 26, and 29–32 were evaluated for activity against herpes viruses and human immunodeficiency virus. None of the compounds were active against the viruses nor were they cytotoxic at the highest concentration tested.     

Comparative stability of 1-alkoxyalkyl alpha-D-glucosides in the presence of acid or alpha-D-glucosidase from yeast

The aminated 1-alkoxyalkyl glycosides [(S)-2-amino-1-methoxyethyl] 6-amino-6-deoxy-alpha-D-glucopyranoside (3) and [(R,S)-1-ethoxyethyl] 6-amino-6-deoxy-alpha-D-glucopyranoside (4) have been synthesised and characterised. These compounds as well as [(R)-2-amino-1-methoxyethyl] alpha-D-glucopyranoside (1) prepared earlier are resistant against alpha-D-glucosidase (maltase, alpha-D-glucoside glucohydrolase, E.C. 3.2.1.20) from yeast, yet undergo hydrolysis under relatively mild acidic conditions. The kinetic parameters of the interaction with alpha-D-glucosidase and with acid were determined. The relative rates of acid hydrolysis of aminated 1-alkoxyalkyl glycosides compared with aminated ordinary glycosides suggest essential differences in the mechanism of acid-catalysed hydrolysis.     

Pyridinium-carbaldehyde: active Maillard reaction product from the reaction of hexoses with lysine residues

Besides the formation of the aminotriazine N6-[4-(3-amino-1,2,4-triazin-5-yl)-2,3-dihydroxybutyl]-L-lysine, the reaction of [1-13C]D-glucose with lysine and aminoguanidine leads to the generation of 6-[2-([[amino(imino)methyl]hydrazono]methyl)pyridinium-1-yl]-L-norleucine (14-13C1). The dideoxyosone N6-(2,3-dihydroxy-5,6-dioxohexyl)-L-lysine was shown to be a precursor in the formation of 14-13C1, which proceeds via the reactive carbonyl intermediate 6-(2-formylpyridinium-1-yl)-L-norleucine (13-13C1). In order to study the reactivity of 13-13C1, the model compound 1-butyl-2-formylpyridinium (18) was prepared in a two-step procedure starting from 2-pyridinemethanol. The reaction of the pyridinium-carbaldehyde 18 with L-lysine yielded the Strecker analogous degradation product 2-(aminomethyl)-1-butylpyridinium and another compound, which was shown to be as 1-butyl-2-[(2-oxopiperidin-3-ylidene)methyl]pyridinium. Reaction of 18 with the C-H acidic 4-hydroxy-5-methylfuran-3(2H)-one leads to the formation of the condensation product 1-butyl-2-[hydroxy-(4-hydroxy-5-methyl-3-oxofuran-2(3H)-ylidene)methyl]-pyridinium.