Preparation and Cleavage of Some Organosilanes Containing Heterocyclic Groups

Abstract

Several tetrasubstituted silanes have been reported in which silicon is attached to the following heterocycles: furan (la), thiophene (la, b, c, d, e, f), dibenzothiophene (lg, h), dibenzofuran (lg), quinoline (Id), and quinoxaline (le).The object of the present investigation was to extend these syntheses to additional heterocyclic1 systems and to study the stability of the silanes in acidic and in basic solution. The general method of synthesis follows that used previously, namely, treatment of a C-lithium derivative of a heterocycle with triphenylchlorosilane in ether solution. The organolithium compounds were prepared by treatment of either the heterocycle or its bromo derivative with n-butyllithium according to known procedures (2). Using these procedures the following triphenylsilanes were prepared in yields based on triphenylchlorosilane ranging from 5 to 71%: 2-benzothiazolyl-, 2-benzothienyl-, 2-and 4-[lg] dibenzothienyl-, 2-[lg] and 4dibenzofuryl-, 5-ethyl-4-carbazolyl-, 5-ethyl-2carbazolyl-, and 8-chloro-5-ethyl-2-carbazolyl-. By treatment of 5-ethyl-2carbazolyllithium with the appropriate chlorosilane, the following silanes were prepared in yields based on the chlorosilane of 25 to 82 %: diphenylbis(5-ethyl-2-carbazolyl)-, phenyltris(5-ethyl-2-carbazolyl)-, and tetrakis(5-ethyl-2-carbazolyl)-.

Organosilicon Derivatives of Sulfur

“…Investigation of the addition of organosilicon thiols to organosilicon vinyl sulfides led to the discovery of the isomerization of organosilicon thioacetals (mercaptals) to symmetrical ethers of l,2-ethanedithiol, which proceeds both in the presence of peroxides and without them, even during distillation in vacuum [1231: In this way it was possible to obtain good yields (60-80%) of 2-thienylsilanes [61,183,268,350,356,879,968], 2-benzothienylsilanes [289,486,670], and 1-,2-,3-, and 4-dibenzothienylsilanes [289,357,361,392,486,670]. It was not possible to synthesize N-triphenylsilylphenothiazine by the reaction of N-phenothiazinyllithium with triphenylchlorosilane indiethyl ether (18 h at room temperature) [352], while the yield of I-thianthrenyltriphenylsilane in the reaction of I-thianthrenyllithium with triphenylchlorosilane is only 9.5% [360].…”

“…Triphenyl (2-benzothiazolyl) silane is also formed inlow yield (5%) by the action of 2-benzothiazolyllithium on triphenylchlorosilane. When triphenylbromosilane is used instead of triphenylchlorosilane, the yield is increased to 19%, but when triphenylsilane is used, no interaction of the reagents is observed [486]. Organoalkoxysilanes have also been used instead of organohalosilanes in reaction (2.273) [357 ].…”

“…A second general method of synthesizing organosilicon sulfurcontaining heterocyclic compounds is the reaction of organomagnesium derivatives of sulfur-containing heterocycles with halosilanes or alkoxysilanes: (2.274) This reaction is used to obtain 2-and 3-thienylsilanes [51,120,185,218,219,268,342,423,599 [486,670]. By this method it is possible to synthesize from 2,5dibromothiophene both monosilicon-substituted thiophenes [51,185] and 2,5-disilicon-substituted thiophenes [91,120].…”

“…The reaction of halogen-substituted sulfur-containing heterocycles with triphenylsilylpotassium or triphenylsilyllithium proceeds according to the scheme (2.275) This reaction has been used for the synthesis of triphenyl-(2-dibenzothienyl)silane [486], and also 2-, 3-, and 4-triphenylsilyl substituted 10-ethylphenothiazines and the sulfone of 3,7bis(triphenylsilyl)-10-ethylphenothiazine [352]. The yields of triphenylsilyl derivatives of 10-ethylphenothiazines vary over the range of 12-40% (45-60% of hexaphenyldisilane is formed in addition to them) [352].…”

SiC-spaltung in 2-thienylsilanen durch sekundäre amine

“…Auch andere nukleophile Reagenzien (Hydroxidionen [7], n-Butyllithium [8]) und geeignete Elektrophile [9] Die Darstellung von Phenyl-dichlorsilan [11], Phenyl·vinYI·dichlorsilan [12] und Diphenyl-vinylsilan [13] erfolgte in Anlehnung an bekannte Vorschrif~en der Literatur. …”