Synthesis of the four stereoisomers of 7-acetoxy-15-methylnonacosane, a component of the female sex pheromone of the screwworm fly, Cochliomyia hominivorax

The four stereoisomers of 7-acetoxy-15-methylnonacosane (1), a component of the female sex pheromone of the New World screwworm fly (Cochliomyia hominivorax) were synthesized. The stereogenic center at C-15 of 1 originated from that of the enantiomers of citronellal, and that at C-7 was generated by lipase-catalyzed asymmetric acetylation of (3RS,11R)- and (3RS,11S)-17-methyl-1-trimethylsilylpentacos-1-yn-3-ol (13). Three of the stereoisomers of 1 showed equivalent good pheromone activity, while the activity of (7R,15R)-1 was weak.     

Steroidal saponins from roots of Asparagus officinalis

Sarsasapogenin M (1) and sarsasapogenin N (2), two new oligospirostanosides with a unique aglycone moiety, (25S)-5beta-spirostan-3beta, 17alpha-diol, along with seven known compounds (25S)-5beta-spirostan-3beta-ol-3-O-beta-d-glucopyranosyl-(1,2)-[beta-d-xylopyranosyl-(1,4)]-beta-d-glucopyranoside (3), (25S)-5beta-spirostan-3beta-ol-3-O-beta-d-glucopyranosyl-(1,2)-beta-d-glucopyranoside (4), (25S)-5beta-spirostan-3beta-ol-3-O-alpha-l-rhamnopyranosyl-(1,2)-[alpha-l-rhamnopyranosyl-(1,4)]-beta-d-glucopyranoside (5), (25S)26-O-beta-d-glucopyranosyl-5beta-furost-20 (22)-ene-3beta,26-diol-3-O-beta-d-glucopyranosyl-(1,2)-beta-d-glucopyranoside (6), yamogenin (7), beta-sitosterol (8), and sitosterol-beta-d-glucoside (9) were isolated from the roots of Asparagus officinalis L. Their structures were determined by spectral analysis, including extensive 1D and 2D NMR experiments.     

The lipid composition of a halotolerant species of Staphylococcus epidermidis.

Studies were carried out on the lipid composition of a halotolerant Staphylococcus epidermidis isolated in pure culture from a growth medium for extreme halophiles containing 25% NaCl. The four major polar lipid components in this bacterium were found to be: (a) glycerophosphoryl diglucosyl diglyceride (10% by weight) with structure 3(1)-O-(-sn-glycerol-1-phosphoryl-6'-O=(beta-D glucopyranosyl-(1 leads to 6)- O-beta-D-glucopyranosyl)-1(3),2-diacyl-sn-glycerol; (b) diglucosyl diglyceride (15% by weight) with structure 3(1)-O-(beta-D-glucopyranosyl (1 leads to 6)-O-beta-D-glucopyranosyl)-1(3),2-diacyl-sn-glycerol; (c) monoglucosyl diglyceride (3% by weight) with structure 3(1)-O-(beta-D-glucopyranosyl)-1(3),2-diacyl-sn-glycerol, and (d) phosphatidylglycerol (60% by weight) with structure 1,2 diacyl-sn-glycero-3-phosphoryl-1'-sn-glycerol. Phosphatidic acid, cardiolipin, lysophosphatidylglycerol and three unidentified phospholipids were also detected in small amounts. Each lipid component had essentially the same fatty acid composition namely, anteiso-15:0 (60-75%), anteiso-17:0 (18-24%), iso-17:0 (8--10%), and small amounts of palmitic and stearic acids (2-5%). The fatty acids were non-randomly distributed in phosphatidylglycerol, the shorter chain anteiso 15:0 fatty acid being exclusively esterified to the 2-position and the longer chain anteiso- and iso-17:0 fatty acids at the 1-position. The fatty acid composition was not affected by increaseing NaCl content in the medium in the rande 0--15% but the proportion of anteiso-15:0 increased greatly when the salt concentration was increased to 25%. The proportions of ionic polar lipids were modified to give an increased net negative charge per mol ionic lipids when NaCl in the medium was increased from 15 to 25%, but the proportions of neutral glycolipids remained fairly constant.     

Microbial transformation of mesterolone

The microbial transformation of mesterolone (= (1alpha,5alpha,17beta)-17-hydroxy-1-methylandrostan-3-one; 1), by a number of fungi yielded (1alpha,5alpha)-1-methylandrostane-3,17-dione (2), (1alpha,3beta,5alpha,17beta)-1-methylandrostane-3,17-diol (3), (5alpha)-1-methylandrost-1-ene-3,17-dione (4), (1alpha,5alpha,15alpha)-15-hydroxy-1-methylandrostane-3,17-dione (5), (1alpha,5alpha,6alpha,17beta)-6,17-dihydroxy-1-methylandrostan-3-one (6), (1alpha,5alpha,7alpha,17beta)-7,17-dihydroxy-1-methylandrostan-3-one (7), (1alpha,5alpha,11alpha,17beta)-11,17-dihydroxy-1-methylandrostan-3-one (8), (1alpha,5alpha,15alpha, 17beta)15,17-dihydroxy-1-methylandrostan-3-one (9), and (5alpha,15alpha,17beta)-15,17-dihydroxy-1-methylandrost-1-en-3-one (10). Metabolites 5-10 were found to be new compounds. All metabolites, except 2, 3, 6, and 7, exhibited potent anti-inflammatory activity. The structures of these metabolites were characterized on the basis of spectroscopic studies, and the structure of 5 was also determined by single-crystal X-ray-diffraction analysis.     

Efficient methods for the synthesis of [2-15N]guanosine and 2'-deoxy[2-15N]guanosine derivatives

The nucleophilic addition-elimination reaction of 2',3',5'-tri-O-acetyl-2-fluoro-O6-[2-(4-nitrophenyl)ethyl]inosine (8) with [15N]benzylamine in the presence of triethylamine afforded the N2-benzyl[2-15N]guanosine derivative (13) in a high yield, which was further converted into the N2-benzoyl[2-15N] guanosine derivative by treatment with ruthenium trichloride and tetrabutylammonium periodate. A similar sequence of reactions of 2',3',5'-tri-O-acetyl-2-fluoro-06-[2-(methylthio)ethyl]inosine (9) and the 6-chloro-2-fluoro-9-(beta-D-ribofuranosyl)-9H-purine derivative (11), which were respectively prepared from guanosine, with potassium [15N]phthalimide afforded the N2-phthaloyl [2-15N]guanosine derivative (15; 62%) and 9-(2,3,5-tri-O-acetyl-beta-D-ribofuranosyl)-6-chloro-2-[15N]phthalimido-9H-purine (17; 64%), respectively. Compounds 15 and 17 were then efficiently converted into 2',3',5'-tri-O-acetyl [2-15N]guanosine. The corresponding 2'-deoxy derivatives (16 and 18) were also synthesized through similar procedures.     

Clerodane and labdane diterpenoids from Nuxia sphaerocephala

Seven diterpenoids including four clerodane and three labdane derivatives, (13S)-ent-7beta-hydroxy-3-cleroden-15-oic acid (1), ent-7beta-hydroxy-2-oxo-3-cleroden-15-oic acid (2), ent-2,7-dioxo-3-clero-den-15-oic acid (3), ent-18-(E)-caffeoyloxy-7beta-hydroxy-3-cleroden-15-oic acid (4) (13S)-ent-18-(E)-coumaroyloxy-8(17)-labden-15-oic acid (5), ent-18-(E)-caffeoyloxy-8(17)-labden-15-oic acid (6), ent-15-(E)-caffeoyloxy-8(17)-labden-18-oic acid (7), have been isolated from an ethyl acetate extract of the leaves of Nuxia sphaerocephala, together with 17 known compounds. 3-Oxolup-20(29)-en-30-al (3-oxolupenal) (8) and 3beta-hydroxylup-20(29)-en-30-al (3beta-hydroxy-lupenal) (9) showed the best inhibitory activity against Plasmodium falciparum with the IC(50) values between 1.55 and 4.67 microg/ml in vitro, respectively. The structure and the relative stereochemistry of the compounds were established on the basis of their spectroscopic properties. The absolute configuration at C-13 of 1 and 5 was determined by the PGME amide procedure.     

An efficient synthesis of 3-fluoro-5-thio-xylofuranosyl nucleosides of thymine, uracil, and 5-fluorouracil as potential antitumor or/and antiviral agents

1,2:5,6-Di-O-isopropylidene-alpha-D-glucofuranose by the sequence of mild oxidation, reduction, fluorination, periodate oxidation, borohydride reduction, and sulfonylation gave 3-deoxy-3-fluoro-1,2-O-isopropylidene-5-O-p-toluenesulfonyl-alpha-D-xylofuranose (5). Tosylate 5 was converted to thioacetate derivative 6, which after acetolysis gave 1,2-di-O-acetyl-5-S-acetyl-3-deoxy-3-fluoro-5-thio-D-xylofuranose (7). Condensation of 7 with silylated thymine, uracil, and 5-fluorouracil afforded nucleosides 1-(5-S-acetyl-3-deoxy-3-fluoro-5-thio-beta-D-xylofuranosyl) thymine (8), 1-(5-S-acetyl-3-deoxy-3-fluoro-5-thio-beta-D-xylofuranosyl) uracil (9), and 1-(5-S-acetyl-3-deoxy-3-fluoro-5-thio-beta-D-xylofuranosyl) 5-fluorouracil (10). Compounds 8, 9, and 10 are biologically active against rotavirus infection and the growth of tumor cells.     

Novel and regiospecific synthesis of 2-amino estrogens via Zincke nitration

An efficient synthesis of 2-aminoestrone (14), 2 aminoestradiol (15), 2-amino-16 alpha-hydroxyestrone (16) and 2-aminoestriol (17) is described. 2,4-Dibromo estrogens 1 - 4 were regiospecifically converted to the corresponding 2-nitro-4-bromo derivatives 5 - 8 in quantitative yields, with Zincke nitration using sodium nitrite. Catalytic hydrogenation of the 2-nitro-4-bromides 5 - 8 over palladium-on-charcoal gave directly the desired 2-amino estrogens 14 - 17 in high yields. The 2-amino compounds 15 and 17 were also obtained by the reduction of the corresponding 2-nitro-4-bromides 6 and 8 with sodium borohydride in the presence of palladium chloride.     

Diaryldimethylpiperazine ligands with mu- and delta-opioid receptor affinity: Synthesis of (+)-4-[(alphaR)-alpha-(4-allyl-(2S,5S)-dimethylpiperazin-1-yl)-(3-hydroxyphenyl)methyl]-N-ethyl-N-phenylbenzamide and (-)-4-[(alphaR)-alpha-(2S,5S)-dimethylpiperazin-1-yl)-(3-hydroxyphenyl)methyl]-N-ethyl-N-phenylbenzamide

We have explored the synthesis of compounds that have good affinity for both mu- and delta-opioid receptors from the (alphaR,2S,5S) class of diaryldimethylpiperazines. These non-selective compounds were related to opioids that have been found to interact selectively with mu- or delta-opioid receptors as agonists or antagonists. In our initial survey, we found two compounds, (+)-4-[(alphaR)-alpha-(4-allyl-(2S,5S)-dimethylpiperazin-1-yl)-(3-hydroxyphenyl)methyl]-N-ethyl-N-phenylbenzamide (14) and its N-H relative, (-)-4-[(alphaR)-alpha-(2S,5S)-dimethylpiperazin-1-yl)-(3-hydroxyphenyl)methyl]-N-ethyl-N-phenylbenzamide (15), that interacted with delta-receptors with good affinity, and, as we hoped, with much higher affinity at mu-receptors than SNC80. The relative configuration of the benzylic position in (+)-4-[(alphaR)-alpha-(4-allyl-(2S,5S)-dimethyl-1-piperazinyl)-(3-methoxyphenyl)methyl]-benzyl alcohol (10) was determined by X-ray crystallographic analysis of a crystal that was an unresolved twin. The absolute stereochemistry of that benzylic stereogenic center was unequivocally derived by the X-ray crystallographic analysis from the two other centers of asymmetry in the molecule that were known. Those were established from the synthesis via a dipeptide cyclo-L-Ala-L-Ala in which the absolute stereochemistry was established.     

Synthesis of some epoxy and/or N-oxy 17-picolyl and 17-picolinylidene-androst-5-ene derivatives and evaluation of their biological activity

Steroidal epoxy and/or N-oxy 17-picolyl and 17-picolinylidene-androst-5-ene derivatives have been prepared using 3beta,17beta-dihydroxy-17alpha-picolyl-androst-5-ene (1), 3beta-acetoxy-17-picolinylidene-androst-5-ene (2), and 3beta-hydroxy-17-picolinylidene-androst-5-ene (3) as synthetic precursors. The compounds 2 and/or 3 were reacted with m-chloroperoxybenzoic acid (MCPBA). The compounds synthesized from 2 were 17-picolinylidene-N-oxide 4, 5alpha,6alpha-epoxy and 5beta,6beta-epoxy-17-picolinylidene-N-oxide 5 and 6, and 5alpha,6alpha:17alpha,20alpha- and 5beta,6beta:17alpha,20alpha-diepoxy-N-oxide 7 and 8. Starting from compound 3, a mixture of 5alpha,6alpha-epoxy and 5beta,6beta-epoxy-17-picolinylidene 9 and 10, 5alpha,6alpha-epoxy and 5beta,6beta-epoxy-17-picolinylidene-N-oxide 11 and 12, and 5alpha,6alpha:17alpha,20alpha- and 5beta,6beta:17alpha,20alpha-diepoxy-N-oxide 13 and 14 were obtained. From compounds 15 and 18, obtained from 1 and 3 by the Oppenauer oxidation, the 4alpha,5alpha-epoxy and 4beta,5beta-epoxy derivatives 16, 17 and 20, 21 were prepared by oxidation with 30% H(2)O(2). Oxidation of 18 with MCPBA yielded only the N-oxide 19. The structures of compounds 15 and 18 were proved by the X-ray analysis. Compounds 1-6, 9, 15, 17, 18, and 21 were tested on activity against the enzyme aromatase. Antitumor activity against three tumor cell lines (human breast adenocarcinoma ER+, MCF-7, human breast adenocarcinoma ER-, MDA-MB-231, and prostate cancer PC3) was evaluated. Three tested compounds (1, 4, and 19) showed strong activity against PC3, the IC(50) values being in the range 0.55-10microM, whereas compound 17 showed strong activity against MDA-MB-231 (IC(50) 10.4microM).     

A precursor to the beta-pyranosides of 3-amino-3,6-dideoxy-D-mannose (mycosamine).

SN2-type reaction of 3-O-(1-imidazyl)sulfonyl-1,2:5,6-di-O-isopropylidene-alpha-D-gluco furanose with benzoate gave the 3-O-benzoyl-alpha-D-allo derivative 2, which was hydrolysed to give the 5,6-diol 3. Compound 3 was converted into the 6-deoxy-6-iodo derivative 4 which was reduced with tributylstannane, and then position 5 was protected by benzyloxymethylation, to give 3-O-benzoyl-5-O-benzyloxymethyl-6-deoxy-1,2-O-isopropylidene-alpha -D- allofuranose (6). Debenzoylation of 6 gave 7, (1-imidazyl)sulfonylation gave 8, and azide displacement gave 3-azido-5-O-benzyloxymethyl-3,6-dideoxy- 1,2-O-isopropylidene-alpha-D-glucofuranose (9, 85%). Acetolysis of 9 gave 1,2,4-tri-O-acetyl-3-azido-3,6-dideoxy-alpha,beta-D-glucopyranose (10 and 11). Selective hydrolysis of AcO-1 in the mixture of 10 and 11 with hydrazine acetate (----12), followed by conversion into the pyranosyl chloride 13, treatment with N,N-dimethylformamide dimethyl acetal in the presence of tetrabutylammonium bromide, and benzylation gave 3-azido-4-O-benzyl-3,6-dideoxy-1,2-O-(1-methoxyethylidene)-alpha-D -glucopyranose (15). Treatment of 15 with dry acetic acid gave 1,2-di-O-acetyl-3-azido-4-O-benzyl-3,6-dideoxy-beta-D-glucopyranose (16, 86% yield) that was an excellent glycosyl donor in the presence of trimethylsilyl triflate, allowing the synthesis of cyclohexyl 2-O-acetyl-3-azido-4-O-benzyl-3,6-dideoxy-beta-D-glucopyranoside (17, 90%).(ABSTRACT TRUNCATED AT 250 WORDS)     

Cytogenetic analysis in 139 Tunisian patients with de novo acute myeloid leukemia

This paper presents the results of a cytogenetic analysis in 139 Tunisian patients with de novo acute myeloid leukemia (AML), including 27 children aged 1-15 years and 112 adults. Mean age was 32 (range 1-75) and the M/F ratio was 1.43. Of our patients, 45% had apparently normal karyotypes. Acquired chromosome aberrations were found in 77 (55% ) patients. t(8;21) was identified in 27 patients (19%); t(15;17) in 13 patients (9%); deletion 7q or monosomy 7 in seven patients (5%); +8 in seven patients (5%); abnormal 16 in four patients (3%); 11q23 rearrangements in two patients (2%) and del(5q), in one patient (1%). The remaining 16 patients had miscellaneous clonal abnormalities. Specific translocations associated with the FAB type were found: t(8;21) with AML2 and t(15;17) with AML3. We concluded that our study in a Tunisian population confirmed the relation between some specific abnormalities and the FAB classification. We found a higher incidence for t(8;21) than usually described.     

Analysis of the steroid binding domain of rat steroid 5alpha-reductase (isozyme-1): the steroid D-ring binding domain of 5alpha-reductase.

We have previously shown that the photoactive 4-azasteroid, [1,2 3H]N-4(benzylbenzoyl)-3-oxo-4-aza-4-methyl-5alpha-androst an-17beta-carboxamide is an effective probe of rat steroid 5alpha-reductase (isozyme-1) (5alphaR-1). In the current investigation, PEG-fractionated (6.5%) detergent-solubilized preparations containing 5alphaR-1 activity were ultraviolet (UV)-photolyzed with [3H]-4MABP and subsequently purified by 8.75% preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The fractions corresponding to the radioactive peak following the dye front were analyzed by 10% sodium dodecyl sulfate-polyacrylamide gel electrophoresis and showed the presence of a single, labeled, 26 KDa protein band, the apparent molecular weight of 5alphaR-1. TCA precipitation of the labeled fractions, followed by long-term digestion of the TCA pellet with chymotrypsin and high-performance liquid chromatography analysis, indicated that the majority of the radioactivity eluted with a peak retention time of 55-56 min. Rechromatography of this fraction using a modified gradient (elution 54-55 min), followed by sequence analysis, yielded a single N-terminal tetrapeptide with the sequence, -L-E-G-F-, corresponding to residues 15-18 of the 5alphaR-1 sequence. Site-directed mutagenesis studies indicated that mutant F18L showed an approximately 12-fold increase in the Km for testosterone, whereas the Km for reduced nicotinomide adenine dinucleotide phosphate remained virtually unaltered.     

Differential expression of ecto-5' nucleotidase activity by functionally and phenotypically distinct subpopulations of human Leu-2+/T8+ lymphocytes

Subsets of Leu-2+/T8+ cytotoxic/suppressor T lymphocytes were isolated by using various methods of purification and were investigated for expression of ecto-5' nucleotidase (5'NT) enzyme activity by radiochemical, cytochemical, and ultrastructural techniques. By using both the radiochemical and the cytochemical methods. T4-OKM1- cells displayed higher 5'NT activity in comparison with the entire T4- subpopulation. Analyses of the subpopulations of T4- (and predominantly Leu-2+) cells defined by the Leu-15 or Lyt-1 (9.3) monoclonal antibodies demonstrated that T4-Leu-15- and T4-Lyt-1+ cells displayed high 5'NT activity, whereas virtually no activity was present in T4-Leu-15+ and T4-Lyt-1-cells. At the ultrastructural level, the 5'NT reaction product was detected on the plasma membrane of a proportion of nongranular Leu-2+/T8+ lymphocytes, but no activity was found on cells with a granular lymphocyte (GL) morphology. 5'NT activity was also analyzed in peripheral blood mononuclear cells from one patient with expanded numbers of GL and two patients with GL leukemia. The enzymatic activity was significantly lower in these patients than in normal controls. This study provides new cytochemical evidence demonstrating the heterogeneity of Leu-2+/T8+ cells, and indicates that the population with the suppressor phenotype and function (Leu-15+/Lyt-1-, GL morphology) displays low or absent 5'NT activity, whereas the population composed of cytotoxic cell precursors (Leu-15-/Lyt-1+, nongranular morphology) has high 5'NT activity. Implications of these data for the interpretation of low 5'NT activity described in several immunodeficiency states and lymphoproliferative disorders are discussed.     

Transcriptional antitermination activity of the synthetic nut elements of coliphage lambda. I. Assembly of the nutR recognition site from boxA and nut core elements

An active nutR antiterminator was reconstructed from two synthetic modules, one containing the 8-bp boxA (5'-CGCTCTTA) and the other the 17-bp nutR core (5'-AGCCCTGAAAAAGGGCA) sequence. The modules were synthesized with HindIII cohesive ends, which upon annealing and ligation created an 8-bp spacer (5'-CAAAGCTT) between the boxA and nutR core. The 8-bp length was the same as in the native nutR (5'-CACATTCC), but the sequence showed less than 38% homology. The antitermination mediated by the synthetic nutR, was 68-80% efficient when tested in the pp-nutR-N-tL1-galK expression plasmid, analogous to that used by Drahos and Szybalski [Gene, 16 (1981) 261-274]. The cloned boxA by itself has no activity, while the nutR core alone shows only marginal (5-10%) antiterminator function. Increasing the distance between boxA and the nutR core from 8 bp to 20-28 bp, i.e., by one to two turns of the DNA helix (about 10 bp per turn), has little effect on the antiterminator function, whereas use of spacers with length about halfway between 8 and 20 bp results in reduced antitermination. It appears that both the sequences and spacial arrangement of the boxA and nut elements are important for efficient antiterminator function.     

Synthesis and cardiovascular activity of metoprolol analogues

The synthesis of four novel analogues of metoprolol, a well-known beta1-blocker used to reduce arterial blood pressure, is described. The preparation of (2S,2'S)-7, (2R,2'S)-7, (2R,2'R)-8, and (2S,2'R)-8 was based on the reaction of racemic 2-[4-(2'-methoxyethyl)-phenoxymethyl]-oxirane (4) with (R)- or (S)-2-amino-1-butanol. Salient characteristics of analogues 7 and 8 relative to metoprolol are the incorporation of an additional stereogenic center, as well as a methyl group and a hydroxyl function on the nitrogen-containing chain. These novel derivatives present significant hypotensive and bradycardiac activity, although no blocking action toward beta1 and beta2 adrenergic receptor.     

Preparation of (5 alpha,13 alpha)-D-azasteroids as key precursors of a new family of potential GABAA receptor modulators

Three groups of (5 alpha,13 alpha)-D-azasteroids, (5 alpha,13 alpha)-3-hydroxy-17a-aza-D-homoandrostans (12), (5 alpha,13 alpha)-3-hydroxy-17-aza-D-homoandrostans (15), and (5 alpha,13 alpha)-3-hydroxy-17-azaandrostans (17), were designed and synthesized as key precursors for the further preparation of a new family of potential GABAA receptor modulators from commercially available natural steroids (5 alpha)-3-hydroxyandrostane-17-ones (7).     

Microbiological transformation of two labdane diterpenes, the main constituents of Madia species, by two fungi

Microbial transformation of 13R,14R,15-trihydroxylabd-7-ene (5) and 13R,14R,15-trihydroxylabd-8(17)-ene (6) by the fungus Debaryomyces hansenii gave 1 (13R,14R,15-trihydroxy-6-oxolabd-8-ene) and 3 (7alpha,13R,14R,15-tetrahydroxy-labd-8(17)-ene), respectively. While, microbial transformation of 5 by Aspergillus niger afforded 2 (3beta,13R,14R,15-tetrahydroxy-labd-7-ene), and 13R,14R,15-trihydroxylabd-8,17-ene (6) gave 3 and 4 (3R,14R,15-3-oxotetrahydroxy-labd-7-ene). The structures of the new compounds, 1 and 2, were assigned by 1D and 2D high-field NMR spectroscopic methods. Antimicrobial activity of these compounds were tested and their MIC were determined.     

Spacer-modified saccharides for the regioselective photoaffinity labelling of the binding site of an immunoglobulin.

The spacer-modified trisaccharides that mimic (1----6)-linked beta-D-galactotetraose (Gal4), namely, O-beta-D-galactopyranosyl-(1----6)-S-beta-D-galactopyranosyl-(1----11)-8 -azi- 6,7,8,9,10-pentadeoxy-11-thio-D-galacto-undecose (12) and O-beta-D-galactopyranosyl-(1----6)-O-beta-D-galactopyranosyl- (1----13)-8-azi-6,7,8,9,10,11,12-heptadeoxy-D-galacto-tri decose (20) were synthesised by coupling disaccharide derivatives with 8-azi-6,7,8,9,10-pentadeoxy-1,2:3,4-di-O-isopropylidene-11-O -tosyl-alpha-D-galacto-undecopyranose (10) and 8-azi-6,7,8,9,10,11,12-heptadeoxy-1,2:3,4-di-O-isopropyli den e-alpha-D-galacto- tridecopyranose (17), respectively. Compounds 12 and 20 had affinities for the combining sites of the antibodies IgA X24 and IgA J 539 similar to those of O-beta-D-galactopyranosyl-(1----6)-O-beta-D- galactopyranosyl-(1----11)-8-azi-6,7,8,9,10-pentadeoxy-D-gal acto-undecose (7) and the native ligand Gal4. Tritium-labelled 7 chemically modified the heavy and light chains of IgA J 539, whereas 8-azi-6,7,8,9,10-pentadeoxy-D-(11-3H)galacto-undecose (5a) reacted only with the heavy chain.