Abstract:
A METHOD OF PROTECTING THE SULFUR ATOM OF CYSTEINE N PEPTIDE SYNTHESIS BY REACTION WITH B-(N,N-DISUBSTITUTED)AMINOETHYL ISOCYANATE IN WHICH ONE SUBSTITUENT IS METHYL OR EHTYL AND THE OTHER IS BENZYLOXYCARBONYL, T-BUTYLOXYCARBONYL, OR ADAMANTYLOXYCARBONYL. FOR REMOVAL OF THE PROTECTIVE GROUP, THE PEPTIDE IS TREATED WITH A STRONG ACID TO FORM THE ACID SALT OF THE CORRESPONDING MONOSUBSTITUTED N-ETHYL OR N-METHYL AMINO COMPOUND AND THEN MADE ALKALINE TO LIBERATE THE AMINE. THE PROTECTIVE GROUP CLEAVES INTRAMOLECULARLY WITH FORMATION OF A METHYL OR ETHYL-SUBSTITUTED IMIDAZOLONE AND THE PEPTIDE IN WHICH THE CYSTEINE SULFUR ATOM IS PRESENT AS SULFHYDRYL.
Abstract:
D R A W I N G A method for making insulin and certain derivatives thereof from a compound of the formula (I)
D R A W I N G wherein X is hydrogen or an S-protective group and n is an integer from two to four, which comprises cleaving any Sprotective groups present and dehydrogenating -SH groups to form S-S bonds to form a compound of the formula (II)
BRIDGE BY TREATING THE LATTER COMPOUND WITH AN ACID. Compounds of the formula II.