The synthesis and preliminary biological testing of some bicyclic guanidine derivatives

Condensation of 2-amino-2-imidazoline with α,β-unsaturated esters yields an imidazo[1,2-a]pyrimidin-7-one system whereas reaction with an acetylenic ester or β-keto esters gives the corresponding unsaturated imidazo[1,2-a]pyrimidin-5-one product. In some cases a non-cyclized product is obtained under milder reaction conditions. Cyclization of ω- (imidazolin-2-ylamino) acids yields fused bicyclic products for the acetic and propionic acid derivatives whereas the butyric acid analogue cyclizes to yield an N-substituted pyrrolidone. Representative examples of all these compounds do not show mutagenic properties in a modified Ames test and are mainly inactive when tested for central nervous system activity.

Irreversible enzyme inhibitors. 200. Active-site-directed inhibitors of deoxycytidine kinase

Forty-three pyrimidine derivatives, mainly containing the 4-aminopyrimidine system, have been prepared and evaluated as inhibitors of deoxycytidine kinase. The most effective inhibitors were 2-alkylthio-4-aminopyrimidines and 1-alky-1-cytosines. The best inhibitors in both groups were those with large alkyl substituents, which indicate that hydrophobic bonding is occurring, possibly in the same area adjacent to the active site.

Hydroxamic acids: VI. The synthesis, properties and reactions of amidic hydroxamic acid and dihydroxamic acid derivatives

Amidic hydroxamic acid and dihydroxamic acid derivatives of maleic, phthalic, fumaric and succinic acids have been prepared and their properties and reactions studied. In particular suitably oriented derivatives of these systems have been investigated to ascertain whether they are capable of existing in, or reacting through, various cyclol tautomers. Attempts to trap the cyclol tautomers are described and these results, together with other indirect chemical evidence as well as the spectral data, suggest that the cyclol tautomer may be present in some cases, in contrast to the corresponding diamides which do not show similar behaviour.

Central nervous system active compounds. II. The synthesis of some 4-, 5-, 6- and 7-substituted caprolactams

The synthesis of caprolactam derivatives substituted at C4, C5, C6 and C7 with alkyl, aryl, acyl and hetero substituents is described. A variety of synthetic approaches to these compounds have been investigated and assessed, particularly for the synthesis of C4- and C6-substituted compounds. A significant number of the C4-, C6- and C7- substituted compounds prepared show central nervous system activity, ranging from convulsants to depressants depending on the position and nature of the substituent group.

Central nervous system active compounds. I. The synthesis of some caprolactam derivatives substituted at N1, C2 and C3

The synthesis of a number of caprolactam derivatives with alkyl, aryl and hetero atom substituents at N1, C2 and C3 is described. Alkylation and arylation at C3 by a variety of methods is discussed. Some of these compounds are powerful convulsing agents; a few are depressants.

Hydroxamic acids. V. The alkylation of O-alkylarylhydroxamic acids

The reactions of O-alkylarylhydroxamic acids with a variety of alkylating agents, to yield mixtures of the N,O-dialkyl and 0,O'-dialkyl products, are described. Spectral data and independent synthesis allow the unambiguous assignment of structure to these isomeric products. Substituents on the aryl ring exert an electronic influence on the ratio of the two products; the extent of this influence varies with the alkylating agent. Diazomethane, triethyloxonium tetrafluoroborate and methyl fluorosulphonate give largely, but not exclusively, the 0,O'-dialkyl product. Methyl fluorosulphonate, in the presence of a base, reacts further to form an unstable salt which appears also to function as an alkylating agent.

Acetylenic Acids. I. The reaction of arylpropiolic acids with carbodiimides

The formation of substituted 1-phenylnaphthalene-2,3-dicarboxylic anhydrides from substituted phenylpropiolic acids by carbodiimides is shown to be a general reaction and proceeds in high yields under mild conditions. Heterocyclic acetylenic acids also form analogous products in high yield. The reaction is confined to α,β-acetylenic acids conjugated with an aromatic ring, as alkylpropiolic acids form mixtures of alkylpropiolic anhydrides and N-acylureas under the same conditions and esters of arylpropiolic acids do not react. The effects of temperature, bases, and solvents on the reaction are described. Some features of the nuclear magnetic resonance spectra of the 1- phenylnaphthalene products are discussed.

The reaction between 2,3-Diphenyl-2H-azirine and Phenyldiazomethane

The reaction between 2,3-diphenyl-2H-azirine and phenyldiazomethane produces the stable 1-azido-1,2,3-triphenylprop-1-ene in good yield. The structure is confirmed by an alternative synthesis which indicates that the double bond has the E-configuration.

Hydroxamic acids. II. The acetylation of O-alkylhydroxamic acids

O-Alkylhydroxamic acids are readily acetylated, in high yield, under mild conditions. Aliphatic O-alkylhydroxamic acids yield only one product, shown to be the N-acetyl derivative. O-Alkylarylhydroxamic acids form both the O- and N- acetyl isomers; the ratio of these isomers depends on electronic and steric effects. Ultraviolet spectral data indicate that the salts of O-alkylarylhydroxamic acids exist predominantly in the hydroximic acid form; however, it is not possible to decide which is the acidic proton of the hydroxamic acid system. The nature of the cation in the salts of O-alkylhydroxamic acids is important in determining the site of acetylation.

Hydroxamic acids. III. Mass spectra of substituted hydroxamic acids and cyclic imides

Aryl hydroxamic acid derivatives fragment in a diagnostic manner upon electron impact. A hydroxamic acid containing both styryl and benzyl substituents undergoes skeletal-rearrangement of the type ABC → AC+B. The mass spectra of the O- and N-acetyl derivatives of O- benzylhydroxamic acids are indistinguishable. M-CO2 fragments are again observed in the mass spectra of several substituted phthalimides.

Hydroxamic acids. IV. The synthesis of O-alkylhydroxamic acids

The synthesis of O-alkylhydroxamic acids by the coupling of alkoxyamines with carboxylic acids using carbodiimides and by the Wolff rearrangement of diazoketones in the presence of alkoxyamines is discussed.

Hydroxamic acids. I. The oxidation of hydroxamic acids and their O-alkyl derivatives

The generality of the formation of an N,O-diacylhydroxylamine from the oxidation of hydroxamic acids in an inert solvent is confirmed for an extended range of oxidizing agents. Oxidation of o-alkylhydroxamic acids with a variety of oxidizing agents yields an ester and small amounts of the corresponding carboxylic acid. No evidence was obtained for an oxidative intramolecular cyclization of an O-alkyl-hydroxamic acid, in cases where this was possible, either in the presence or absence of ultraviolet irradiation.

Porphyrins. II. The synthesis of porphyrins from 2-aminomethylpyrroles

Benzyl 5-formyl-3,4-dimethylpyrrole-2-carboxylate oxime (VI; R = COOCH2Ph) has been reduced and treated with cupric acetate to yield copper octamethylporphin in 20% yield. Copper octaethylporphin was obtained in similar yield from 2-formyl-3,4-diethylpyrrole oxime (VII). The porphyrins are also obtained, in much smaller yield, following acid-catalysed condensation; a by- product formed under these latter conditions is probably a biladiene. Attempts to prepare meso-substituted porphyrins by similar treatment of the oximes of 2-acetyl- and 2-benzoyl-pyrroles were unsuccessful.

Quassin

Nuclear magnetic resonance evidence and additional chemical evidence are reported which supports structure (II) for quassin. A table of the N.M.R. assignments for quassin and four derivatives is included.