The chemical synthesis of glucosaminylphosphatidylglycerol. Comparison with a new phospholipid isolated from Bacillus megaterium

1. We describe the synthesis of a glucosamine derivative of phosphatidylglycerol having the same structure as that of the natural compound isolated from Bacillus megaterium. 2. 2-O-(3,4,6-Tri-O-acetyl-2-deoxy-2-phthalimido-d-glucopyranosyl)-3-O-benzyl-1-iodo-sn-glycerol was prepared by a Königs–Knorr condensation between 3-O-benzyl-1-toluene-p-sulphonyl-sn-glycerol and 3,4,6-tri-O-acetyl-1-bromo-2-deoxy-2-phthalimido-d-glucopyranose followed by replacement of the toluene-p-sulphonyl group with iodine. The iodide was treated with the silver salt of 2-isolauroyl-1-oleoyl-sn-glycerol 3-(monobenzyl hydrogen phosphate) to form the fully protected phosphoglycolipid. 3. Removal of benzyl protecting groups by catalytic hydrogenolysis, phthaloyl group with hydrazine and acetyl groups with pH10 buffer furnished 2-O-(2-amino-2-deoxy-d-glucopyranosyl)-1-(2-isolauroyl-1-stearoyl-sn-glycero-3-phosphoryl)-sn-glycerol. 4. The synthetic and natural compounds appeared identical when compared by chromatography and by identification of hydrolysis products from chemical and enzymic degradations.