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2-Ethoxy- and 2-(ethylthio)-1-azetines readily undergo 1,3-dipolar cycloadditions with nitrile oxides and nitrile ylides to give stable 4,5-bicyclic cycloadducts. With nitrilimines, however, the expected 1,3-dipolar cycloadducts and/or unexpected ring-opened products, namely 1,2,4-triazoles, are formed depending on the nature of the nitrilimine N-substituent. In contrast, the azetines fail to react with nitrile sulphides, azomethine ylides, nitrones, aryl azides, and various dienes. X-ray crystallographic data on the nitrile oxide, nitrile ylide, and nitrilimine cycloadducts, and on the 1,2,4-triazoles, are presented. Also a mechanistic rationale for triazole formation is offered.

Thermolysis, in boiling o-dichlorobenzene, of the cycloadducts 5 and 10a,b of diphenylcyclopropenone and 2-(alkylthio)azetines 4 and 9a,b yield the title compound 8.

A versatile route for the preparation of 2-ketomethylene phospholipids using dithiane chemistry is described.

The synthesis of some quinazolino[3,2-a][1,4]benzodiazepines from 2-bromomethyl-3-o-carbomethoxyphenyl-4(3H)quinazolone is described. Alkylation and acylation of N-6 led to a series of novel derivatives of this ring system.

The synthesis of (±)-cis- and (±)-trans-4-isopropenylpyrrolidin-3-ylacetic acids and the attempted synthesis of (±)-2,3-trans-,3,4-cis-2-carboxy-4-isopropenylpyrrolidin-3-ylacetic acid, α-kainic acid, by intramolecular ene reactions are described. The ene cyclisation reaction has been shown to be kinetically controlled with the relative stabilities of the transition states controlling the product distribution. No isomerisation of starting diene or product pyrrolidine occurs under the conditions of the reaction.

4H-Imidazo[2,1-c][1,4]benzoxazine-2-carboxylic acid (3) was found to possess potent activity in the IgE-induced rat passive cutaneous anaphylaxis model which may be predictive of clinical antiallergic activity. Compared to disodium cromoglycate (DSCG, 1), 3 was less active following iv administration but unlike DSCG showed very significant oral activity. To explore the structural requirements for this activity, a range of tricyclic compounds was prepared and their activities were measured. Individual 2-carboxylic acids derived from imidazo[1,2-a]quinolines, imidazo[1,2-a]quinoxalines, imidazo[1,2-a]quinoxalinones, pyrrolo[1,2-a]quinoxalinones, pyrrolo[2,3-a]quinoxalinones, and imidazo[2,1-b]benzothiazoles showed iv activities up to 10(3) times as potent as DSCG and many of them showed significant oral activity. From these, imidazo[1,2-a]quinoxaline-2-carboxylic acid 114 has been chosen for further development.

The fate of a novel imidazo-benzodiazepine (I) was studied in male rats and rabbits using 14C and 3H-labelled I. In both species the compound was rapidly and widely absorbed after an oral dose of 5 mg/kg to give peak tissue and plasma levels after 1 hour in the rat and 4 hours in the rabbit. The highest concentrations of radioactivity were present in the liver (rat) and liver, kidney and subcutaneous fat (rabbit). Plasma levels of radioactivity fell to 3% of the maximum value in 24 hours in the rat but 48 hours were required for a similar fall in the rabbit. The main route of elimination of radioactivity was via the bile followed by excretion in the faeces. For the rat the rate of biliary elimination was 16.6% of the administered dose/hour; for the rabbit this rate was 5.6%/hour. Recovery of administered radioactivity during 0-24 hours for urine and faeces respectively was 4.8% and 69% for the rat and 23.2% and 10.9% for the rabbit. Up to 97% of the radioactivity administered to rats could be recovered in the excreta in the 7 days following dosing. Up to 90% of the dose administered to rabbits appeared in the excreta during 10 days. No unchanged (I) could be detected in the urine or bile. The radioactive metabolites were polar products, some of which were in the form of glucuronide conjugates.

Hydrazines, in contrast to amines, yield mainly imine tautomers on addition to dimethyl acetylenedicarboxylate.

A route to peptide analogues incorporating the replacement of an amide bond with a trans-carbon–carbon double bond is presented and applied to the synthesis of a Leu5–enkephalin analogue.

Michael-type additions of phenylsulphinylacetate esters to αβ-unsaturated ketones produce cyclohexane-1,3-dione derivatives, which, after thermal elimination of benzenesulphenic acid, give the corresponding 5-substituted resorcinols, such as olivetol. The scope of this entry into other aromatic systems, such as 3,5-disubstituted and 2,3,5-trisubstituted phenols and orsellinic acid has been explored.

The synthesis of some cyclic sulphoximides is reported, and their n.m.r. data interpreted to show the lack of aromaticity in these systems.