Gustav Schroll

Studies in mass spectrometry—XV : Mass spectra of sulphoxides and sulphones. The formation of CC and CO bonds upon electron impact☆

Abstract Although dialkyl sulphoxides and sulphones behave relatively simply upon electron impact, aromatic sulphoxides and sulphones show a pronounced tendency to undergo CO bond formation, as evidence by a number of decomposition pathways which involve the elimination of carbon monoxide. For example, dibenzothiophene dioxide (XV) decomposes from its molecular ion by successive eliminations of carbon monoxide.

Studies in mass spectrometry—XVII : Rearrangement processes in some esters containing unsaturated linkages—the elimination of CO2 from esters☆

Abstract The mass spectra of a variety of propiolate, acetylenedicarboxylate, maleate, fumarate and cyanoacetate esters have been measured. The formation of ions via the elimination of carbon dioxide (with or without the associated loss of other groups) is quite common in these esters. The prevalence of such fragmentation processes, which are of obvious importance with respect to the element-mapping technique, is probably associated with the presence of double or triple bonds (in the vicinity of the ester function) which may be ionized by removal of an electron and thus provide an electron deficient site to which a group (alkyl, alkenyl, etc.) may migrate.Abstract The mass spectra of a variety of propiolate, acetylenedicarboxylate, maleate, fumarate and cyanoacetate esters have been measured. The formation of ions via the elimination of carbon dioxide (with or without the associated loss of other groups) is quite common in these esters. The prevalence of such fragmentation processes, which are of obvious importance with respect to the element-mapping technique, is probably associated with the presence of double or triple bonds (in the vicinity of the ester function) which may be ionized by removal of an electron and thus provide an electron deficient site to which a group (alkyl, alkenyl, etc.) may migrate.

Studies in mass spectrometry—XX : Bond-forming reactions occurring in the fragmentation of some α,β-unsaturated esters and nitriles upon electron impact☆

Abstract Bond-forming reactions which occur in the decomposition of some α,β-unsaturated esters and nitriles upon electron impact are described. The reactions include bond formation between adjacent phenyl and cyanide substituents in structures of type A, and alkoxyl (or hydroxyl) migrations (probably by 1,3-shifts) in systems of type B, to give ions represented by C. A previously described cyclization reaction is shown to facilitate the expulsion of an ortho-substituent (at the site of cyclization) in a phenyl ring relative to the corresponding meta- and para-substituents.

The mass spectra of nitrones : CO bond formation upon electron impact☆

Abstract The mass spectra of a series of nitrones are reported and discussed. All spectra contain molecular ions, and the majority of fragment ions owe their genesis to skeletal-reorganization of the molecular ion. Fragmentation modes have been substantiated by high-resolution data and appropriate metastable ions. Deuterium labelling has been used to elucidate the MH process which is observed in many spectra.

Electron impact studies—IX : Mass spectra of arylsulphinylamines skeletal rearrangement on electron impact☆

Abstract The mass spectra of sixteen arylsulphinylamines are reported and discussed. The spectra exhibit pronounced molecular ions and large skeletal rearrangement fragments. The fragmentation modes have been substantiated by high resolution measurements, appropriate metastable ions and deuterium labelling studies. In several cases ‘ortho effects’ enable the determination of both the position and nature of the ortho substituent in substituted sulphinylanilines.

The Crystal and Molecular Structure of Delta9-Tetrahydrocannabinolic Acid B.

The crystal and molecular structure of the title compound C-22H-30O-4, has been determined by X-ray methods using 1106 reflections above background level collected by counter methods. The crystals are orthorhombic, space group P2-12-12-1 with cell dimensions a equals 16.514(2) A; b equals 14.324(2) A; c equals 8.744(1) A; there are four molecules per unit cell. The structure was refined to an R of 0.084 (weighted R-w equals 0.068). The cyclohexene and the pyran part of the molecule occurs in the half-chair conformation. The bond distances and angles, and a slight twist of the benzene ring, indicate considerable stains in the aromatic system. Both the phenolic and carboxylic group are significantly out of the plane through the aromatig ring. The angle between this plane and a plane through the cyclohexene ring is 37.7 degrees. The pentyl sidechain occurs in an extended gauche conformation, and the thermal parameters of this part of the molecule are very high. The molecules are held together by van der Waals forces in the c-directions, and hydrogen bonds (2.688 A) from phenolic to carboxylic groups in the a-b plane. There is a short ultra-molecular hydrogen bond (2.490 A) from the carboxylic group to the pyran oxygen.

o-Hydroxyphenyl alkyl sulphides, -sulphoxides, and -sulphones: A synthetic and spectroscopic investigation

Abstract The title compounds have been synthesized and studied by means of NMR, IR, and UV spectra with special attention to H-bonding. These compounds appeared to exist in the chelated form. Furthermore, a detailed investigation of the electron-impact mass-spectra has been carried out,-in the case of sulphoxides, by means of a computer-monitored mixture analysis.