MonodentateN coordination of 1aza4oxo1,3butadienes [R1NC(R2)C(R3)O] to platinum(II). X-ray structure of trans-[PtCl2(PEt3){σ-N-(t-BuNCHC(Me)O)}]

Reaction of dimeric trans-[PtCl₂(PR₃)]₂ with 1-aza-4-oxo-1,3-butadienes [R¹NC(R²)C(R³)O, R³ = Me, Ph, OMe, NEt₂] in a 1:2 molar ratio results in almost quantitative formation of mononuclear complexes trans·[PtCl₂(PR₃){σ-N-(R¹NC(R²)C(R³)O)}]. The ligands are bonded in the monodentate σ-N bonding mode to the platinum(II) centre. This has been established by an X-ray structure determination of trans-[PtCl₂(PEt₃){σ-N-(t-BuNCHC(Me)O)}]. Crystals of the latter compound are orthorhombic with space group Pc2₁n; cell constants are a = 14.712(3), b = 15.053(2), c = 9.025(5) Å, Z= 4 and R_w = 0.056 for 3281 reflections. The 1aza4oxol,3butadiene (α-iminoketone for R³ is alkyl or aryl) has the E-configuration about the imine bond (CN 1.34(4) Å), with a C(5)C(6) distance of 1.44(5) Å and a NC(5)/ C(6)O torsion angle of 89(4)°. As a result of this ligand conformation, the acetyl hydrogen atoms are positioned (on average) into the neighbourhood of the Pt-atom above the Pt-coordination plane. Infrared and NMR (¹H, ¹³C, ³¹p) data show that these structural features are also predominant in solution.     

Conformation of 2,3-diformylglycerol, a model compound of membrane phospholipids

The conformations of 2,3-diformylglycerol, a model compound of the diacylglycerol portion of phospholipids, were analyzed both by the classical potential function method and by the INDO molecular orbital method. The results suggest that in membranes, the conformation of the diacylglycerol portion of phospholipids is such that the two ester planes of the β- and γ-hydrocarbon chains stack in an antiparallel way with the dihedral angles β′{C(3)C(2)O(21)C(21)} ? 270° and γ₁{C(2)C(3)O(31)C(31)} ? 270°.     

Effect of long-term L-dopa administration on the dopaminergic and cholinergic (muscarinic) receptors of striatum in 6-hydroxydopamine lesioned rats

L-Dihydroxyphenylalanine (L-Dopa) (200 mg/kg/day) was administered for 30 days to the rats whose nigrostriatal dopamine pathway was lesioned unilaterally with 6-hydroxydopamine and the receptor binding of ³H-spiperone and ³H-quinuclidinyl benzilate (³HQNB) was measured in the dopaminergic and muscarinic cholinergic receptors of the striatum. ³H-spiperone binding increased by 73% and ³HQNB binding decreased by 14% in the lesioned side when compared to the control side of L-Dopa-non-treated rats. ³H-spiperone binding was measured in the lesioned sides of L-Dopa-treated and L-Dopa-non-treated rats and was found to have decreased by 21% in the former. In the control side of the L-Dopa-treated lesioned rats, however, ³H-spiperone binding increased by 27% when compared to the opposite striatum of the same rats. ³HQNB binding in the lesioned side of L-Dopa-treated rats was not significantly different from that of the control side statistically. These results suggest that changes in functional equilibrium between the dopaminergic and cholinergic mechanisms influence the muscarinic cholinergic receptors and that supersensitivity of dopamine receptors after lesion of the nigrostriatal pathway also remains after long-term L-Dopa treatment.     

The crystal structure of 2-deoxy-β-d-arabino-hexopyranose at −150°

2-Deoxy-β-d-arabino-hexopyranose, C₆H₁₂O₅, is orthorhombic, P2₁2₁2₁, with cell dimensions at ?150° [20°], a = 6.484(2) [6.510(3)], b = 10.364(2) [10.427(4)], c = 11.134(3) [11.153(5)] Å, V = 748.2 [757.1] ų, Z = 4, D_x = 1.457 [1.440], and D_m = [1.455] g.cm^?3. The intensities of 1269 reflections were measured by using MoKα radiation. The structure was solved by direct methods, and refined by full-matrix least-squares, with anisotropic, thermal parameters for the carbon and oxygen atoms, and isotropic parameters for the hydrogen atoms. The pyranose has the ⁴C₁(d) conformation, with puckering parameters Q = 0.563 Å, θ = 3.9°, and ? = 350.3°. The departure from ideality is very small, and less than that in β-d-glucopyranose, Q = 0.584 Å and θ = 6.9°. The β-glycosidic, CO bond is short, 1.383(4) Å, and the OCOH torsion angle is ?87°, consistent with the anomeric effect. The hydrogen-bonding scheme consists of infinite chains, with side chains terminating at a ring-oxygen atom.     

Vibrational spectra of the diammineplatinum(II) disodium 5′-uridine monophosphate blue complex

The blue complexes produced by reaction of cis-diamminediaquoplatinum(II) nitrate, [cis-Pt(NH₃)₂(H₂O)₂](NO₃)₂, with disodium 5′-uridine monophosphate, 5′-UMP(Na₂), in H₂O and D₂O have been investigated by FT-IR spectroscopy. On the basis of the spectral changes observed in the CO stretching region during the reactions, chelation of the amidate N(3)··O(2) moiety to Pt(II) appears to be more likely than N(4)··O(4) chelation. The antisymmetric PO stretching mode of the PO_3²⁻ group of 5′-UMP splits into a triplet on complex formation indicating that PO_3²⁻ plays an important role in the structure of the platinum blue complexes. In addition, the sugar moiety of 5′-UMP apparently adopts a predominantly C(3′)-endo conformation in the solid blue complex. Finally, Raman microprobe spectroscopy of the solid provides some evidence for PtN(3) bond formation.     

Crystal structure of methyl 2,6-dichloro-2,6-dideoxy-3,4-O-isopropylidene-α-D-altropyranoside. A pyranoside system close to a skew-boat conformation

The crystal structure of methyl 2,6-dichloro-2,6-dideoxy-3,4-O-isopropylidene-α-D-altropyranoside (1) has been determined by X-ray diffraction. The compound crystallizes in the orthorhombic system, space group P2₁2₁2₁, with unit-cell dimensions a  7.932, b  8.133, and c  20.447 Å. The structure was solved by the heavy-atom method and refined by the least-squares technique to an R value of 0.047 by using 736 intensities measured on a diffractometer. The pyranoside ring is close to a skew-boat conformation, with C-2 and C-5 being maximally displaced from the least-squares plane through the remaining four atoms. The H-1H-2 dihedral angle of  158° is in agreement with the J_1,2 value of 4.5 Hz. Thus the solid-state conformation appears to correspond with the conformation in solution. The dioxolane ring is in a twist form, with O-4 and, C-8 puckered on opposite sides of the plane of the other ring atoms. The pyranose-ring substituents are in equatorial and pseudoequatorial orientations. The hydrogen atoms at C-3 and C-4 are in a cis arrangement. The orientations of both the methoxyl group and the chloromethyl group with respect to the ring are gauche—trans. The exocyclic anomeric C-1O-1 bond-distance (1.39 Å) is the shortest CO bond in the structure. The intracyclic CO bonds are significantly different, C-1O-5 being less than C-5O-5.     

High resolution nuclear magnetic resonance spectroscopy of glycosphingolipids. I: 360 MHz 1H and 90.5 MHz 13C NMR analysis of galactosylceramides

The high resolution ¹H and ¹³C nuclear magnetic resonance (NMR) spectra of galactosylceramides containing n-fatty acids and α-hydroxy fatty acids were recorded in dimethylsulfoxide solution with and without addition of D₂O. From the coupling constants of the sugar ring protons, a ⁴C₁ conformation can be deduced. In contrast to the conformation in aqueous solution, the C⁶ hydroxymethylene group is freely rotating around the C⁶C⁵ bond. In the ceramide residue all signals produced by protons linked to carbons bearing electronegative substituents could be attributed. The large difference in coupling constants of the methylene protons of C^1′ to the C^2′ methine proton of the sphingosine indicates a restricted rotation around the C^1′C^2′ bond. The assignments of the hydroxy and amino protons follow from the decoupling of the corresponding methine protons.     

Letter: Conformation of the cystine linkages in bovine alpha-lactalbumin as revealed by its Raman effect

In the Raman spectrum of 10% bovine α-lactalbumin in neutral aqueous solution, two Raman lines assignable to the SS stretching vibrations have been observed at 507 and 540 cm^?1, with an intensity ratio of 3:1. From this fact, it has been concluded that, of the four CCSSCC linkages in the molecule of this protein, three are in the gauche-gauehe-gauche conformation, whereas one is in the trans-gauche-trans conformation.     

Quantum-chemical and empirical calculations on phospholipids. II. A conformational analysis of model headgroups of phospholipids obtained by the PCILO-procedure.

The conformational behaviour and the charge distribution of methylphosphorylcholine has been analyzed within the framework of the PCILO method including phosphorus-oxygen σ- and π-bonds. In the global minimum of energy the OPOCC chain has a (?synclinal, ?synclinal, ?syn/anticlinal, +anticlinal) conformation.     

6-Azauridine, a nucleoside with unusual ribose conformation. The molecular and crystal structure

The cytostatic analogue ribo-6-azauridine crystallizes in the orthorhombic space group P2₁2₁2₁ with eight molecules per unit cell of dimensions $\text{a = 20.230, b = 7.709, c = 12.863}\text{A}\text{?}$. A trial structure was obtained by direct methods. Least-squares refinement of co-ordinates and anisotropic thermal parameters based on 1998 reflections measured on a four-circle diffractometer led to a discrepancy index R = 4.0%. Like uridine, 6-azauridine has the anti conformation about the glycosidic bond and a C(3′)-endo sugar pucker. Unlike uridine, it exhibits a close approach of N(6) to C(2′) at only 2.814 and 2.844 Å in the two independent molecules, and a C(5′)(5′) bond that is gauche to C(4′)O(1′) but trans to C(4′)C(3′); this conformation about a C(4′)C(5′) bond has never been observed before for C(3′)-endo puckered riboses in the crystalline state. The crystal structure displays a pseudo-A face centering and very similar conformational parameters for the two independent molecules. Every OH and NH group in the structure serves as a proton donor in a hydrogen bond, including an unusual N(3)—H(3) … O(1′) link. Molecular orbital calculations by the extended Hückel method indicate that from uridine to 6-azauridine the net charge changes sign at ring positions 5 and 6 and disappears at 1.     

Synthesis and spectroscopic properties of CpRuCl(R-DAB(4e)) and CpRuCo(CO)3(R-DAB(6e)). Part XVII. X-ray structure determination of CpRuCo(CO)3(t-Bu-DAB(6e))

CpRuCl(PPh₃)₂ reacted with excess R-DAB in refluxing toluene to give CpRuCl(R-DAB(4e)) (1a: R = i-Pr; 1b: R = t-Bu; 1c: R = neo-Pent; 1d: R =p-Tol). ¹H NMR and ¹³C NMR spectroscopic data indicated that in these complexes the R-DAB ligand is bonded in a chelating 4e coordination mode.Reaction of 1a and 1b with one equivalent of [Co(CO)₄]⁻ afforded CpRuCo(CO)₃(R-DAB(6e)) (2a: R = i-Pr; 2b: R = t-Bu). The structure of 2b was determined by a single crystal X-ray structure determination. Crystals of 2b are monoclinic, space group P2₁/n, with four molecules in a unit cell of dimensions: a = 16.812(4), b = 12.233(3), c = 9.938(3) Å and β = 105.47(3)°. The structure was solved via the heavy atom method and refined to R = 0.060 and R_w = 0.065 for the 3706 observed reflections. The molecule contains a RuCo bond of 2.660(3) Å and a cyclopentadienyl group that is η⁵-coordinated to ruthenium [RuC(cyclopentadienyl) = 2.208(3) Å (mean)]. Two carbonyls are terminally coordinated to cobalt (CoC(1) = 1.746(7) and CoC(2) = 1.715(6) Å) while the third is slightly asymmetrically bridging the RuCo bond (RuC(3) = 2.025(6) and CoC(3) = 1.912(6) Å). The RuC(3)O(3) and CoC(3)O(3) angles are 138.4(5)° and 136.5(5)°, respectively. The t-Bu-DAB ligand is in the bridging 6e coordination mode: σ-N coordinated to Ru (RuN(2) = 2.125(4) Å), μ₂-N′ bridging the RuCo bond and η²-CN coordinated to Co (RuN(1) = 2.113(5), CoN(1) = 1.941(4) and CoC(4) = 2.084(5) Å). The η²-CN′ bonded imine group has a bond length of 1.394(7) Å indicating substantial π-backbonding from Co into the anti-bonding orbital of this CN bond.¹H NMR spectroscopy indicated that 2a and 2b are fluxional on the NMR time scale. The fluxionality of 6e bonded R-DAB ligands is rarely observed and may be explained by the reversible interchange of the σ-N and η²-CN′ coordinated imine parts of the R-DAB ligand.     

f-Element/crown ether complexes. 16. Synthesis,crystallization and crystal structure of [Dy(OH2)8]Cl3·18-crown-6·4H2O

When crystals of [Dy(OH₂)₇(OHMe)] [DyCl(OH₂)₂(18- crown-6)]₂Cl₇·2H₂O [1] are allowed to warm from 5 °C to ambient temperature (22 °C) under the original solvent mixture (1:3 CH₃OH: CH₃CN), they redissolve and the title complex can be isolated by slow evaporation of the resulting solution. The crystal structure of this complex, [Dy(OH₂)₈]Cl₃·18-crown-₆·4H₂O, has been determined. It crystallizes in the monoclinic space group, P2₁/c, with a = 10.395(1), b = 18.684(1), c = 16.259- (3) Å, β= 102.56(1)°, and D_calc = 1.61 g cm⁻³ for Z = 4. A final conventional R value of 0.041 was obtained by least-squares refinement using 3453 independent observed [F_o⩾5σ(F_o)] reflections. The [Dy(OH₂)₈]³⁺ cations and crown ether molecules are hydrogen bonded in a polymeric chain with the crown molecules separating the cations and a total of seven DyOH₂···O(crown ether) hydrogen bonds. The chains are connected by a hydrogen bonding network consisting of the cations, chloride ions, and uncoordinated water molecules. The geometry of the cation is best described as a bicapped trigonal prism with distortions on the reaction pathway toward dodecahedral symmetry. The two capping atoms average 2.41(1) Å from Dy, the remaining DyO distances average 2.38(2) Å. The 18-crown-6 molecule has the D_3d conformation normally observed except for a distortion of one OCCO unit containing the oxygen atom accepting two hydrogen bonds.     

Interaction of MgATP2− with DNA: Assessment of metal binding sites and DNA conformations by spectroscopic and thermal denaturation studies

Spectroscopic (IR, UV, CD and fluorescence) and thermal denaturation studies of native calf thymus DNA, DNAMgATP²⁻ and DNAMg²⁺ have been carried out in aqueous KBr medium (introduced by the present authors as a very effective solvent for DNA). The IR data recorded for the systems indicate that MgATP²⁻ binds to the N₇ and C₆O of the guanine residue of DNA forming a five-membered chelate ring. The data also suggest that despite binding to the guanine bases, Mg²⁺ binds more strongly to the phosphate moiety of DNA. Solution CD spectra of DNA, DNAMgATP²⁻ and DNAMg²⁺ indicate that in each case DNA exists in the B conformation. Thin-film CD studies reveal that irrespective of the relative humidity conditions, pure DNA as well as that after interaction with Mg²⁺ show a structural transition B → C, conformationally, although belonging to the B family. A similar study shows that DNA on interaction with MgATP²⁻ assumes a more packed conformation (B)_n giving rise to a ψ⁻ spectrum. Steady-state as well as dynamic fluorimetric studies clearly indicate that MgATP²⁻ does not intercalate between CGGC base pairs. The thermal denaturation studies support the IR data with respect to the metal binding sites and the mode of binding in both cases.     

Crystal Structure and Conformation of 5‐Fluorouridine: Conformational Preferences for 5‐Fluorinated Pyranosides

Crystals of 5‐fluorouridine (5FUrd) have unit cell dimensions a = 7.716(1), b = 5.861(2), c = 13.041(1)Å, α = γ = 90°, β = 96.70° (1), space group P2₁, Z = 2, ρ_obs = 1.56 gm/c.c and ρ_calc = 1574 gm/c.c The crystal structure was determined with diffractometric data and refined to a final reliability index of 0.042 for the observed 2205 reflections (I ≥ 3σ). The nucleoside has the anti conformation [χ = 53.1(4)°] with the furanose ring in the favorite C2′–endo conformation. The conformation across the sugar exocyclic bond is g⁺, with values of 49.1(4) and ? 69.3(4)° for Φ_θc and Φ_∞ respectively. The pseudorotational amplitude τ_m is 34.5 (2) with a phase angle of 171.6(4)°. The crystal structure is stabilized by a network of N–H…O and O–H…O involving the N3 of the uracil base and the sugar O3′ and O2′ as donors and the O2 and O4 of the uracil base and O3′ oxygen as acceptors respectively. Fluorine is neither involved in the hydrogen bonding nor in the stacking interactions. Our studies of several 5‐fluorinated nucleosides show the following preferred conformational features: 1) the most favored anti conformation for the nucleoside [χ varies from ? 20 to + 60°] 2) an inverse correlation between the glycosyl bond distance and the χ angle 3) a wide variation of conformations of the sugar ranging froni C2′–endo through C3′–endo to C4′–exo 4) the preferred g⁺ across the exocyclic C4′–C5′ bond and 5) no role for the fluorine atom in the hydrogen bonding or base stacking interactions.     

Synthesis and crystal and molecular structure of a methyl N,N-diethylcarbamylmethylenephosphonato dysprosium thiocyanate complex

Bis-Methyl N,N-diethylcarbamylmethylenephosphonato dysprosium thiocyanate, Dy[O₂P(OCH₃)CH₂C(O)N(C₂H₅)₂]₂(NCS) was prepared from the combination of ethanolic solutions of Dy(NCS)₃·xH₂O and (CH₃O)₂P(O)CH₂C(O)N(C₂H₅)₂. The complex was characterized by infrared and NMR spectroscopy, and single crystal X-ray diffraction methods. The crystal structure was determined at 25 °C from 3727 independent reflections by using a standard automated diffractometer. The complex was found to crystallize in the monoclinic space group P2₁/c with a = 13.282(4) Å, b = 19.168(5) Å, c = 9.648(2) Å, β = 90.09(2)°, Z = 4, V = 2456.4 ų and ?_cald = 1.72 g cm^?3. The structure was solved by standard heavy atom techniques, and blocked least-squares refinement converged with R_f = 4.7% and R_wF = 4.9%. The Dy atom is seven coordinate and bonded in a bidentate fashion to two anionic phosphonate ligands [O₂P(OCH₃)CH₂C(O)N(C₂H₅)₂^?] through the carbonyl oxygen atoms and one of two phosphonate oxygen atoms. In addition, each Dy atom is coordinated to two phosphonate oxygen atoms from two neighboring complexes and to the nitrogen atom of a thiocyanate ion. This coordination scheme gives rise to a two-dimensional polymeric structure. Some important bond distances include DyNCS 2.433(8) Å, DyO(carbonyl)_avg 2.39(2) Å, DyO(equat. phosphoryl)_avg 2.303(8) Å, DyO(axial phosphoryl)_avg 2.25(2), PO(phosphoryl)_avg 1.493(3) Å and CO(carbonyl)_avg 1.25(1) Å.     

Theoretical drug design: 6-azauridine-5'-phosphate--its X-ray crystal structure, potential energy maps, and mechanism of inhibition of orotidine-5'-phosphate decarboxylase.

The cytostatic drug 6-azauridine is converted in vivo to 6-azauridine-5′-phosphate (z⁶Urd-5′-P), which blocks the enzyme orotidine-5′-phosphate decarboxylase (Ord-5′-Pdecase) and therefore inhibits the de novo production of uridine-5′-phosphate (Urd-5′-P). In order to relate the structure and function of z⁶Urd-5′-P, it was crystallized as trihydrate, space group P2₁2₁2₁ with a = 20.615 Å, b = 6.265 Å, c = 11.881 Å, and the structure established by Patterson methods. Atomic parameters were refined by full-matrix least-squares methods to R = 0.066 using 1638 counter measured x-ray data. The ribose of z⁶Urd-5′-P is in a twisted C(2′)-exo, C(3′)endo conformation, the heterocycle is in extreme anti position with angle N(6)-N(1)-C(1′)-O(4′) at 86.3°, and the orientation about the C(4′)-C(5′) bond is gauche, trans in contrast to gauche, gauche found for all the other 5′-ribonucleotides. Conformational energy calculations show that z⁶Urd-5′-P may adopt an extreme anti conformation not allowed to Urd-5′-P, and they also predict the same unusual trans, gauche conformation about the C(4′)-C(5′) bond in orotidine-5′-phosphate (Ord-5′-P) and in z⁶Urd-5′-P, which renders the distances O(2)…O(5′) in z⁶Urd-5′-P and O(7)…O(5′) in Ord-5′-P comparable. On this basis the function of z⁶Urd-5′-P as an Ord-5′-Pdecase inhibitor can be explained as being due to its structural similarity with the substrate Ord-5′-P and further clarifies the inhibitory action of 5′-nucleotides bearing the heterocycles oxipurinol, xanthine, or allopurinol [J. A. Fyfe, R. L. Miller, and T. A. Krenitsky, J. Biol. Chem. 248 , 3801 (1973)]. With this in mind, new inhibitors for Ord-5′-Pdecase may be designed.     

Transport of muscarinic cholinergic receptors in the sciatic nerve of rat

On the basis of the specific [³H]quinuclidinyl-benzilate binding, the transport of muscarinic cholinergic receptors has been demonstrated in the ventral horn, sciatic nerve and in the 3 mm segments proximal and distal to the ligature of rat sciatic nerves ligated for 24 h (a) without electrolytic lesion, (b) six days after lesion of the spinal ganglia, (c) six days after lesion of the motoric axons, and (d) six days after transection of the sciatic nerve. The distribution of these receptors was also studied in the ventral spinal horn, dorsal root sensory axons, spinal ganglia and sciatic nerve of rabbit.Our results suggest that the receptors are transported in the sciatic nerve of rat. This transport consists of a large anterograde, and a discrete retrograde flow of muscarinic cholinergic receptors. Most of the receptors are possibly synthesized in the motoneuron cell bodies and migrate in the motoric axons; to a lesser extent they may also be synthesized in the cell bodies of the dorsal root ganglia and migrate in the sensory axons of the sciatic nerve.     

31P n.m.r. studies of complexes of NADPH and NADP+ with Escherichia coli dihydrofolate reductase

We have measured the ³¹P n.m.r. spectra of NADP⁺ and NADPH in their binary complexes with Escherichia coli dihydrofolate reductase and in ternary complexes with the enzyme and folate or methotrexate. The ³¹P chemical shift of the 2′ phosphate group is the same in all complexes; its value indicates that it is binding in the dianionic state and its pH independence suggests that it is interacting strongly with cationic residue(s) on the enzyme. Similar behaviour has been noted previously for the complexes with the Lactobacillus casei enzyme although the ³¹P shift is somewhat different in this complex, possibly due to an interaction between the 2′ phosphate group and His 64 which is not conserved in the E. coli enzyme. For the coenzyme complexes with both enzymes ³¹POC₂¹H_2′ spin-spin interactions were detected (7.5–7.8 Hz) on the 2′ phosphate resonances, indicating a POC₂H_2′ dihedral angle of 30 or 330 : this is in good agreement with the value of 330° measured in crystallographic studies¹ (Matthews et al., 1978) on the L. casei enzyme. NADPH-MTX complex. The pyrophosphate resonances are shifted to different extents in the various complexes and there is evidence that there is more OPO bond angle distortion in the E. coli enzyme complexes than in those with the L. casei enzyme. The effects of ³¹POC₅¹H_5′ spin coupling were detected on one pyrophosphate resonance and indicate that the POC₅H_5′ torsion angle has changed by at least ～30° on binding to the E. coli enzyme: this is considerably less than the distortion (～50°) observed previously in the L. casei enzyme complex.     

Effects of prolyl-leucyl-glycinamide and cyclo(leucyl-glycine) on morphine-induced antinociception and brain μ, δ and κ opiate receptors

The effects of prolyl-leucyl-glycinamide and cyclo (leucyl-glycine) on morphine-induced antinociception in mice and on $\text{in vitro}$ binding of ³H-ligands for opiate receptor subtypes (μ, δ and κ) the mouse brain homogenate were determined. Subcutaneous administration of either of the above peptides (1, 2, and 4 mg/kg) 10 min prior to the injection of morphine did not affect morphine-induced antinociception as evidenced by the identical ED₅₀ values of morphine in vehicle and peptide treated groups. The binding of ³H-dihydromorphine and ³H-naloxone ( μ receptors), ³HDAla²DLeu⁵-enkephalin (δ receptors), and ³H-ethylketocyclazocine (κ receptors) to opiate receptors in the mouse brain homogenate was also unaffected by both the peptides over a large concentration range. It is concluded that these peptides do not interact with brain opiate receptors.     

Conformational dependence of CH(CD)-strechings in D-glucose and some deuterated derivatives as revealed by infrared and raman spectroscopy

The Raman and i.r. spectra in the CH- and CD-stretching region of D-glucose and five selectively deuterated derivatives in the solid state have been recorded. The CH (CD) bonds have different force constants depending on their position and conformation in the pyranose ring and on the dihedral angle HCOH (DCOH). Calculations of the intensities of the i.r. bands confirm these conclusions. Modifications of the force field are proposed that account for the changes in the spectra for solutions in D₂O, which are useful for the interpretation of vibrational c.d. spectra.