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Additionsreaktionen von 3-Dimethylamino-2,2-dimethyl-2H-azirin an Isothiocyanate


Schmid, Ursula; Heimgartner, Heinz; Schmid, Hans; Oberhänsli, Willi E (1976). Additionsreaktionen von 3-Dimethylamino-2,2-dimethyl-2H-azirin an Isothiocyanate. Helvetica Chimica Acta, 59(8):2768-2785.

Abstract

Addition Reactions of 3-Dimethylamino-2,2-dimethyl-2H-azirine and Isothiocyanates. The title azirine readily reacts with two molecules of benzyl- or methylisothiocyanate to form the zwitterionic 1:2 addition compounds 4 and 13, respectively (Scheme 2). The presumed 1:1 addition products, which are intermediates in the formation of 4 and 13, cannot be detected. The structure of 4 and 13 follows from their spectroscopic and chemical properties. With water they give the thiourea derivates 5 and 14, respectively; treatment with aqueous acid leads to the 1,3-thiazolin-5-on-derivates 7 and 15,respectively. With sodium borohydride compounds 8 and 16, respectively, are obtained (Scheme 2). The zwitterionic compounds 4 and 13 are able to react further with one molecule of the isothiocyanates to give, in high-yield, triazines 9 and 18, respectively (Scheme 3). The structure of these compounds was again derived from their spectroscopic data. The mechanism for the formation of 9 and 18 is given in Scheme 3. Acid catalysed hydrolysis of 9 and 18 lead to the trithio- cyanuric acid derivates 12 and 20, and to the spire compounds 11 and 19, respectively (Scheme 6). Reaction of 4 with one molecule of phenylisocyanate gives triazine 10 (Scheme 5). According to the X-ray analysis of the methyl compound 18, there are strong steric interactions in this molecule which are due to the side chain. This is demonstrated by the small distances between C(2)...C(13), N(7)…C(11), and C(8)...C(11) (Table 4). These steric interactions, in addition, cause widening of the bond angles N(1)--C(2)--N(7) and C(9)-N(10)-C(11) (Fig. 2).
Furthermore, the triazine ring is no longer planar. This deformation of the ring diminishes repulsion between the methyl groups C(13) and C(15).

Abstract

Addition Reactions of 3-Dimethylamino-2,2-dimethyl-2H-azirine and Isothiocyanates. The title azirine readily reacts with two molecules of benzyl- or methylisothiocyanate to form the zwitterionic 1:2 addition compounds 4 and 13, respectively (Scheme 2). The presumed 1:1 addition products, which are intermediates in the formation of 4 and 13, cannot be detected. The structure of 4 and 13 follows from their spectroscopic and chemical properties. With water they give the thiourea derivates 5 and 14, respectively; treatment with aqueous acid leads to the 1,3-thiazolin-5-on-derivates 7 and 15,respectively. With sodium borohydride compounds 8 and 16, respectively, are obtained (Scheme 2). The zwitterionic compounds 4 and 13 are able to react further with one molecule of the isothiocyanates to give, in high-yield, triazines 9 and 18, respectively (Scheme 3). The structure of these compounds was again derived from their spectroscopic data. The mechanism for the formation of 9 and 18 is given in Scheme 3. Acid catalysed hydrolysis of 9 and 18 lead to the trithio- cyanuric acid derivates 12 and 20, and to the spire compounds 11 and 19, respectively (Scheme 6). Reaction of 4 with one molecule of phenylisocyanate gives triazine 10 (Scheme 5). According to the X-ray analysis of the methyl compound 18, there are strong steric interactions in this molecule which are due to the side chain. This is demonstrated by the small distances between C(2)...C(13), N(7)…C(11), and C(8)...C(11) (Table 4). These steric interactions, in addition, cause widening of the bond angles N(1)--C(2)--N(7) and C(9)-N(10)-C(11) (Fig. 2).
Furthermore, the triazine ring is no longer planar. This deformation of the ring diminishes repulsion between the methyl groups C(13) and C(15).

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Department of Chemistry
Dewey Decimal Classification:540 Chemistry
Language:German
Date:1976
Deposited On:05 Nov 2014 10:19
Last Modified:05 Apr 2016 18:28
Publisher:Wiley-Blackwell Publishing, Inc.
ISSN:0018-019X
Funders:Schweizerischer Nationalfonds zur Förderung der wissenschaftlichen Forschung
Publisher DOI:https://doi.org/10.1002/hlca.19760590816

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