Zhu, Shuguang (1997) Generation of 1,3-dipoles containing carbon, nitrogen, sulphur and phosphorus. Doctoral (PhD) thesis, Memorial University of Newfoundland.
PDF (Migrated (PDF/A Conversion) from original format: (application/pdf))
- Accepted Version
Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission.
Most of the known 1,3-dipoles of propargyl-allenyl type (A≡B⁻-C˙) are composed of carbon, nitrogen and oxygen. Very few 1,3-dipoles of this type contain atoms from the third or lower periods. The nitrile sulphide (R-C≡N⁻-S˙), a recently discovered family of 1,3-dipoles, incorporates sulphur in its π manifold. Our attempts to isolate this very reactive intermediate proved that a bulky group, adamantyl (C₁₀H₁₅-), could not appreciably stabilize it. -- Our synthesis of the bis(nitrile sulphides) or their synthetic equivalents started with the adamantyl (1,3-C₁₀H₁₄-) substituent. 1,3-Bis(1’,3’,4’-oxathiazol-2’-one-5'-yl)-adamantane 3-28a, the precursor for the 1,3-bis(nitrile sulphide)-adamantane 3-20a, was prepared and its cycloaddition reactions to DMAD and 1,3-bis(cyano)adamantane were examined. It was found that the bis(nitrile sulphide) 3-20a had a comparable reactivity to that of adamantyl nitrile sulphide 2-6. 1,8-Bis(1’,3’,4'-oxathiazol-2'-one-5’-yl)-octane 3-28b, another precursor for bis(nitrile sulphide) 3-20b, was also prepared but others such as 1,1-bis(1',3',4'-oxathiazoI-2'-one-5'-yl)-methane 3-28c and 1,4-bis(1',3',4'-oxathiazol-2’-one-5’-yl)-benzene 3-28d could not be synthesized from similar reactions of the corresponding amides with CISC(O)CI due to the strong hydrogen bonding existing in the amides. The conjugated phenyl isothiazolyl oxathiazolones 3-41 and 3-42 were synthesized and their cycloaddition reactions to dipolarophiles were examined. The possibility of producing the poly(isothiazoles) from these oxathiazolones will be discussed. -- A novel synthetic route to the precursor, 1,3,4-oxathiazol-2-one, has been discovered. A better starting material, N,O-bis(trimethyIsiIyl)carbonamide 4-7, was used to replace the amide in the reaction to avoid the strong hydrogen bonding. Several oxathiazolones such as 5-methyl-1,3,4-oxathiazol-2-one 4-4a, 5-(4'-biphenyl)-1,3,4-oxathiazol-2-one 4-4c, 1,4-bis(1’,3',4'-oxathiazol-2'-one-5’-yl)-benzene 4-4d and 4,4'-biphenyl-bis(1”,3",4"-oxathiazol-2”-ones) 4-4e were prepared through the new route. -- The reactions of amides 5-21 with C1SC(O)CI were proposed to synthesize the heterocycles 5-22 which were supposed to be the precursors to the new 1,3-dipoles 5-23. The reactions of p-toluenesulfinamide/N,N-bis(trimethylsilyl)-p-toluenesulfinamide 5-24 with CISC(O)CI did not give the expected precursor 5-22 but p-toIuenedisulfide 5-25, p-toluenethiol-p-toluenesulfonate 5-26 and cyanuric acid 5-27. Benzenesulfonamide/p- toluenesulfonamide with CISC(O)CI did not give any product but the amides themselves. A new reaction of adamantyl phosphaalkyne 5-37 with elemental sulphur with or without Et₃N present in toluene was tested for the synthesis of phosphaalkyne sulphide 5-38.
|Item Type:||Thesis (Doctoral (PhD))|
|Additional Information:||Bibliography: leaves 142-156.|
|Department(s):||Science, Faculty of > Chemistry|
|Library of Congress Subject Heading:||Heterocyclic compounds--Dipole moments; Heterocyclic compounds--Synthesis; Ring formation (Chemistry); Nitriles; 1,3-dipoles|
Actions (login required)