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Please use this identifier to cite or link to this item: http://repository.iitr.ac.in/handle/123456789/3045
Title: Reactions of 4-isothiocyanato-4-methyl-2-pentanone with substituted o-phenylenediamines and their kinetic studies
Authors: Sondhi S.M.
Gupta B.
Sahu R.
Verma R.P.
Published in: Indian Journal of Chemistry - Section B Organic and Medicinal Chemistry
Abstract: o-Phenylenediamine, 4-methyl-1, 2-phenylenediamine, and 4-methoxy-1, 2-phenylenediamine react with 4-isothiocyanato-4-methyl-2-pentanone at room temperature to give isomeric mixture of 1-(2′-aminoaryl)-6-hydroxy-4, 4, 6-trimethyl-1, 4, 5, 6-tetrahydropyrimidine-2-(3H)thiones (2a-c) which on refluxing with catalytic amount of sulphuric acid cyclize to yield pyrimidobenzimidazoles (3a-c). The same products are also obtained by direct condensation of o-phenylenediamine, 4-methyl-1, 2-phenylenediamine and 4-methoxy-1, 2-phenylenediamine with 4-isothiocyanato-4-methyl-2-pentanone. The isomeric 1-(2′-aminoaryl)-6-hydroxy-4, 4, 6-trimethyl-1, 4, 5, 6-tetrahydropyrimidine-2(3H)thiones (2′) and pyrimidobenzimidazoles (3′) are not formed. The structures of 2b, c and 3b, c have been confirmed by synthesizing the same compounds by unambiguous route reported by us recently. Kinetic studies of cyclization of 2a-c to 3a-c have been carried out under pseudo first order conditions in acidic media. The values of rate constant, kobs follows the sequence 2b (R = CH3) > 2a (R = H) > 2c (R = OCH3) indicating their reactivity sequence.
Citation: Indian Journal of Chemistry - Section B Organic and Medicinal Chemistry (1996), 35(6): 572-577
URI: http://repository.iitr.ac.in/handle/123456789/3045
Issue Date: 1996
ISSN: 3764699
Author Scopus IDs: 7006090710
7402195167
7006054505
7402268435
Author Affiliations: Sondhi, S.M., Department of Chemistry, University of Roorkee, Roorkee 247 667, India
Gupta, B., Department of Chemistry, University of Roorkee, Roorkee 247 667, India
Sahu, R., Department of Chemistry, University of Roorkee, Roorkee 247 667, India
Verma, R.P., Department of Chemistry, University of Roorkee, Roorkee 247 667, India
Corresponding Author: Sondhi, S.M.; Department of Chemistry, University of Roorkee, Roorkee 247 667, India
Appears in Collections:Journal Publications [CY]

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