Sigthor Petursson

Synthesis of deoxynojirimycin and of nojirimycin δ-lactam

Abstract The syntheses of nojirimycin δ-1actam and of deoxynojirimycin from a divergent ido-furanose intermediate are reported.

Short efficient synthesis of the α-L-fucosidase inhibitor, deoxyfuconojirimycin [1,5-dideoxy-1,5-imino-L-fucitol] from D-lyxonolactone

The only protection required in a five-step synthesis of the α-L-fucosidase inhibitor, deoxyfuconojirimycin [1,5-dideoxy-1,5-imino-L-fucitol] from D-lyxonolactone, a readily available chiral pool material, is a single isopropylidene group.

Tin(II) chloride catalyzed reactions of diazodiphenylmethane with vicinal diols in an aprotic solvent. The reactions with cis- and trans-1,2-cyclohexanediols and 1,2-propanediol

The paper reports the tin(II) chloride catalyzed reactions of diazodiphenylmethane with the cis- and trans-1,2-cyclohexanediols and R,S-1,2-propanediol in 1,2-dimethoxyethane and the identification of the monodiphenylmethyl ethers formed. The catalyst is shown to work for both the cis- and trans-cyclohexanediols, but the catalyst is unstable at high reagent concentrations, especially in the case of the trans-isomer. Conditions where catalyst destruction is negligible show that the rate of the reaction with the trans-isomer is larger than with the cis-isomer. The reactions with 1,2-propanediol show small difference between the selectivity for the primary and secondary hydroxyl groups. This is in contrast with the tin(II) chloride catalyzed reactions of diazomethane and diazophenylmethane in methanol with carbohydrates, glycerol and ribonucleosides, where the primary hydroxyl group does not react.

Tuneable regioselectivity during the mono-etherification of the 2,3-diol of a mannose derivative

The paper reports selective mono-etherification of the 2-, and 3-hydroxyl groups of methyl 4,6-O-isopropylidene-α-d-mannopyranoside using tin(II) chloride catalysed reactions of diaryldiazomethanes. By the use of different diazo compounds and the variation of the tin(II) chloride concentration the ether formation can be shifted from over 90% 3-selectivity to over 90% 2-selectivity.

Synthesis of δ-(l-α-aminoadipoyl)-l-cysteinyl-d-(O-methyl)-d-allothreonine a substrate for isopenicillin-N synthase and its O-methyl-d-threonine epimer

Abstract The paper describes the synthesis of two epimeric tripeptides δ-( l -α-aminoadipoyl)- l -cysteinyl- d -(O-methyl)- d -threonine (13) and δ-( l -α-aminoadipoyl)- l -cysteinyl- d -(O-methyl)- d -allothreonine (14), modified substrates for the isopenicillin-N synthase enzyme. The d -allothreonine tripeptide (14) has been shown to be an excellent substrate for the enzyme whereas the d -threonine epimer did not react at all. The compound formed by the enzyme with the d -allothreonine tripeptide is a new 2-α-methoxypenicillin.

Enzymatic synthesis of a new type of penicillin

A new antibacterial penicillin, containing a 2-α-methoxy group, has been obtained by enzymatic synthesis from the tripeptide δ-(L-α-aminoadipoyl)-L-cysteinyl-D-(O-methyl-allothreonine) with isopenicillin N synthetase derived from Cephalosporium acremonium CO 728[δ-(L-α-aminoadipoyl)= 5-(5S)-amino-5-carboxypentanoyl].

2-O-Benzhydryl-3,4-(S)-O-benzyl­idene-d-lyxono-1,4-lactone

X-ray crystallography unequivocally showed that protection of the free hydroxyl group of 3,5-O-benzylidene-d-lyxono-1,4-lactone with diphenyldiazomethane proceeded with retention of configuration to give the title compound, C25H22O5. The crystal structure consists of layers of interlocked molecules lying parallel to the a axis.