Abstract: Maytansinoids of the formula: ##STR1## wherein R is hydrogen or alkyl of 1 to 15 carbon atoms are produced by contacting, in the presence of a carbodiimide, maytansinol with a carboxylic acid of the formula:R--COOHwherein R has the same meaning as defined above.In accordance with a second aspect of the invention there are provided novel maytansinoids of the formula ##STR2## wherein R' is hydrogen, n-butyl or alkyl of 5 to 15 carbon atoms.

Abstract: Novel imidazole derivatives of the formula ##STR1## wherein R.sup.1 is hydrogen, nitro or amino, R.sup.2 is a phenyl, furyl or thieyl group which may be substituted by halogen, lower alkyl, lower alkoxy or di-lower-alkylamino, R.sup.3 is hydrogen or lower alkyl and X is halogen, and their physiologically acceptable salts, have excellent diuretic and hypotensive actions.

Abstract: Maytansinoid compounds are produced by(a) treating a compound of the formula ##STR1## wherein alk is ##STR2## --CH.sub.2 CH.sub.2 CH.sub.3 or ##STR3## under conditions of reductive hydrolysis to yield maytinsinol; and (b) contacting the maytansinol with an acid of the formula ##STR4## wherein R is lower alkyl, in the presence of a carbodiimide to yield a maytansinoid.In accordance with a second aspect of the invention there is provided a D-form maytansinoid with respect to the asymmetric center at the 2'-position having the formula: ##STR5## wherein R is a lower alkyl group.

Abstract: New compounds of the formula ##STR1## (wherein R.sub.1 represents a lower alkyl group: and ##STR2## represents an alkylidene radical in which at least one of R.sub.2 and R.sub.3 is a lower alkyl which may optionally be substituted by phenyl, phenyl or a 5- or 6-membered aromatic ring including S, N or O, and the remainder, if any, is hydrogen; ora cycloalkylidene radical of up to six carbon atoms, to which a benzene ring may optionally be fused).These compounds are produced by reacting the corresponding 6-acyloxy compounds with a compound of the formula ##STR3## The new compounds have antiviral activity and are useful to prolong the life spans of tumor-bearing animals.

Abstract: Maytansinoid compounds are produced by contacting in the presence of a carbodiimide the compound maytansinol ##STR1## with an acid of the formula: ##STR2## wherein R is lower alkyl, to yield the desired maytansinoids HAVING THE RESULTANT FORMULA: ##STR3## wherein R is lower alkyl. The maytansinoids (I) are both antifungal agents and also antitumor agents.The D-form (with respect to assymetry at the 2'-position) of the maytansinoids (I) represents a new class of compounds having antifungal and antitumor properties.

Abstract: Maleonitrile is obtained as a dominant product of the reaction between cyanoacetylene and hydrogen cyanide. The yield of maleonitrile is remarkably higher than that in any of known processes.

Abstract: Isonitrosomalonic acid esters, which are useful as a starting material for synthesizing sweet peptides and other chemicals, are prepared by allowing a nitrosating agent to act on a corresponding alkyl alkoxycarbonyl acetoimidate.