Showing papers by "Alan R. Katritzky published in 1988"

Alkylaminonitrobenzenes by vicarious nucleophilic amination with 4-(alkylamino)-1,2,4-triazoles

Abstract: Amination of the nitrobenzenes (I) with the N-alkylaminotriazoles (II) leads to the formation of the 4-(alkylamino)nitrobenzenes (III).

The chemistry of benzotriazole. Part 8. A novel two-step procedure for the N-alkylation of amides

Abstract: Benzotriazole, aldehydes RCHO, and amides R1CONH2 react together with elimination of water to form 1:1:1 adducts which are reduced smoothly by NaBH4 to give the N-substituted amides R1CONHCH2R. Both steps occur in high yields and can be carried out on a large scale, thus comprising a convenient general method for the N-alkylation of amides.

Substituted o-iodoso- and o-iodoxybenzoic acids. Synthesis and catalytic activity in the hydrolysis of active phosphorus esters and related systems

Abstract: Influence d'acides iodosyl-2 et iodyl-2 benzoiques sur la vitesse d'hydrolyse du (diphenyl nitro-4 phenyl) phosphate, de l'(isopropyl O-[nitro-4 phenyl] phenyl) phosphinate, et de l'hexanoate de p-nitrophenyle

The chemistry of benzotriazole. 10. A conceptually new approach to the synthesis of secondary amides and thioamides

Abstract: Amides and thioamides of type RC(=X)NHCHR 1 R 2 are prepared in high yield with the formation of a new C-R 2 bond by the action of a Grignard reagent (R 2 MgX) on the readily available adducts from an amide RCONH 2 (or thioamide RCSNH 2 ), aldehyde R 1 CHO, and benzotriazole

A conceptually new approach to the synthesis of secondary amides and thioamides

Abstract: Amides and thioamides of type RC(=X)NHCHR 1 R 2 are prepared in high yield with the formation of a new C-R 2 bond by the action of a Grignard reagent (R 2 MgX) on the readily available adducts from an amide RCONH 2 (or thioamide RCSNH 2 ), aldehyde R 1 CHO, and benzotriazole

Flash-vacuum pyrolysis of N-vinylbenzotriazoles: formation of N-phenylketenimines

Abstract: A real-time analysis of the flash-vacuum pyrolysis products of 1-vinyl-, 1-(2-methylprop-1-enyl)-, and 1-styryl-benzotriazole (3), (16), and (18) has been performed by tandem mass spectrometry. In the 500–700 °C temperature range, these compounds lose nitrogen yielding the N-phenylketenimines (14), (17), and (19), respectively. At higher pyrolysis temperatures (3) gives indole (4)via isomerization of (14), whereas from (16) the secondary products of (17) are benzene and methacrylonitrile. In a preparative pyrolysis of (18) at 800 °C 2- and 3-phenylindole (9) and (10) respectively, have also been detected.

Polymers by the reaction of bis(pyrylium salts) with diamines: A novel approach to ionene polymers

Abstract: The following reactions of pyrylium salts with amines are described: (1)bis(pyrylium salts) with amines; (2) diamines with pyrylium salts; and (3) bis(pyrylium salts) with diamines. Both (1) and (2) give bis(pyridinium salts) in high yields, and (3) gives the corresponding polymers which are isolated and characterized. This procedure was applied to cationic bis(pyrylium salts) to give cationic dimers and polymers, and further to zwitterionic bis(pyrylium salts) to yield the corresponding zwitterionic dimers and polymers.

Comparative study of the 13C nuclear magnetic resonance shifts of carbonyl and thiocarbonyl compounds

Abstract: The 13C spectra of nine novel and fifteen known derivatives YC(:X)Z with X = O or S are reported and compared with literature data. Two linear relationships between 13CO and 13CS are established depending on whether or not Y or Z is linked through an O atom to the CX group. General equations for 13CO and 13CS in terms of the attached groups are also deduced. The 13C chemical shifts of n-butyl and n-octyl groups attached to the heteroatoms in this series of compounds are recorded and discussed.

The preparation and fungicidal activity of a series of thiazolyl- and isothiazoiyl-diarylcarbinols

Abstract: (Isothiazol-5-yl)diarylcarbinols were prepared from 5-lithioisothiazole. (Thiazol-5-yl)diarylcarbinols were obtained via 5-lithio-2-bromothiazole or 5-lithio-2-trimethylsilylthiazole with subsequent removal of the 2-substituent. Corresponding 2-aminothiazol-5-ylcarbinols were made by protecting 2-aminothiazole as its bis(trimethylsilyl) derivative. Biological activities were compared to the calculated electron densities at the heterocyclic N-atoms.

The synthesis and chemistry of azolenines. Part 8. The Paal-Knorr reaction with cyclic 2-(acylmethyl)-2-alkyl-1,3-diketones: isolation of 1-acyl-1H-pyrroles via rearrangement

Abstract: Treatment of cyclic 2-acylmethyl-2-alkyl-1,3-diketones with ammonium acetate under reflux in acetic acid gives moderate to high yields of 1-acyl-1H-pyrroles by rearrangement. Some of the cyclic diketones react quantitatively with liquid ammonia to yield 2-hydroxy-3,4-dihydro-2H-pyrroles, which are converted in high yields into 1-acyl-1H-pyrroles by a number of methods. Possible mechanisms for the rearrangement are discussed, a process involving transannular interaction within an eight- or nine-membered ring being favoured. Improved methods for the mono- and bis-C-alkylation of cyclic 1,3-diketones are also described.

A 13C study of hydroxymethyl derivatives of five-membered ring heterocycles

Abstract: The 13C spectra of the hydroxymethyl derivatives of pyrrole, furan, 5,5-dimethylhydantoin, imidazole, thiophene, pyrazole, and phenol have been studied and assigned. The substituent parameters for the hydroxymethyl group in pyrrole, thiophene, furan, and imidazole were determined.

Photodissociation and Collisionally Activated Dissociation Studies of N-Alkylpyridinium Cations Formed By Laser Desorption

Abstract: A series of N-alkylpyridinium salts was studied by laser desorption mass spectrometry. Laser desorption was shown to produce gaseous N-alkylpyridinium cations quite easily from the relatively nonvolatile salts. Gas-phase dissociation studies revealed that these cations dissociate by two different mechanisms involving either a direct C-N bond cleavage or a more complicated cleavage involving proton transfer.