Acta Chimica 111. (1982)
1. szám - ORGANIC CHEMISTRY - Shafiullah–Islamuddin: Mass Fragmentation of a Ring-A Aromatized 6-Azasteroid (Short Communication)
Acta Chimica Academiae Scientiarum Ilungaricae, Tomus 111 (1), pp. 1 — 3 (1982) MASS FRAGMENTATION OF A RING-A AROMATIZED 6-AZASTEROID (SHORT COMMUNICATION) ShAFIULLAH* and ISLAMUDDIN (Steroid Research Laboratory, Department of Chemistry, Aligarh Muslim University, Aligarh-202001, India) Received August 5, 1980 In revised form February 27, 1981 Accepted for publication March 25, 1981** Papers correlating the structures and mass spectra of lactams are known in the literature [1, 2]. The present communication is concerned with the mass spectral examination of 19-nor-6-aza-B-homocholesta-l,3,5(10)-trien-7-one (1) [3]. The mass spectrum of lactam 1 gave the molecular ion peak (1') at m/z 381 (base peak), along with fragment ion peaks (2, 4, 5) due to the cleavage of rings C, D and the side chain [4]. Ion peaks (3, 6, 7, 8) are also obtained owing to carbonyl directed fragmentation [5, 6]. Modes a, b, c, d and e explain the genesis of these ions under electron impact. Experimental The mass spectrum was recorded on an AEIMS-9 mass spectrometer at 70 eV, using the direct insertion technique at a source temperature of about 250 °C. The mass composition and relative abundance of the fragment ions are given in Table I. Table I Fragment ion m/z Composition Abundance, % M+ 381 ^28^39^^ 100 M+ CII3 366 C*H«NO 7.9 M+ — CO 353 CÄN 6.5 2 226 CMIIleNO 5.3 3 184 CI3IIMN 9.1 4 172 C„H10NO 7.9 5 167 C12Hl3 50 6 146 C„H3NO 15.7 7 120c7h0no 17.1 8 118CjH^O 28.9 * To whom correspondence should be addressed ** In final form accepted november 26, 1981 Acta Chim. Acad. Sei. Hung. Ill, 1982