Intramolecular Michael-type additions. II. Synthesis of derivatives of 7-thia-2-azabicyclo[3.2.1]oct-3-ene, a novel heterocyclic ring system

1980 ◽  
Vol 58 (8) ◽  
pp. 794-802 ◽  
Author(s):  
Marion E. M Baggs ◽  
Brian Gregory
Keyword(s):  
Sodium Hydroxide ◽  
Ammonium Hydroxide ◽  
Heterocyclic Ring ◽  
Ring System ◽  
Spectroscopic Methods ◽  
The Novel ◽  
Derivatives Of ◽  
By Products

The isothiouronium salt derived from dimethyl 4-chloromethyl-1,4-dihydro-2,6-dimethylpyridine-3,5-dicarboxylate reacted with ammonium hydroxide to give dimethyl 7-thia-2-aza-1,3-dimethylbicyclo[3.2.1]oct-3-ene-4,8-dicarboxylate, which could be converted back to a dihydropyridine using iodomethane. Replacement of ammonium hydroxide by sodium hydroxide afforded a tetrahydro- and a dihydrothieno[3,4-c]pyridine as by-products. 3,5-Diacetyl-4-chloromethyl-1,4-dihydro-2,6-dimethylpyridine reacted with thiourea, followed by ammonium hydroxide, to give 3-acetyl-2-methylpyrrole, 4-acetyl- and 4,8-diacetyl-7-thia-2-aza-1,3-dimethylbicyclo[3.2.1]oct-3-ene. The structure and stereochemistry of the novel 7-thia-2-azabicyclo[3.2.1]octenes are established using spectroscopic methods. The mechanism of their formation is discussed in terms of Baldwin's rules.

Pyrido [2,3-d] thieno [3,2-b] [6H]thiopyran - ein neues heterocyclisches Ringsystem [1] / Pyrido [2,3-d]thieno[3,2-b] [6 H]thiopyran - a New Heterocyclic Ring System [1]

1979 ◽  
Vol 34 (11) ◽  
pp. 1573-1575 ◽  
Author(s):  
Klaus Beelitz ◽  
Klaus Praefcke ◽  
Salo Gronowitz
Keyword(s):  
Uv Irradiation ◽  
Benzene Solution ◽  
Heterocyclic Ring ◽  
Ring System ◽  
Spectroscopic Methods ◽  
System 1

Abstract UV irradiation of S-(3′-thienyl)2-chloro-thionicotinate (1) in benzene solution leads via dehydrohalogenation and cy clization in competition to α-cleavage to formation of thio-lactone 2 besides aldehyde 3 and disulphide 4. 2 contains a new heterocyclic ring system which has been confirmed by spectroscopic methods.

scholarly journals Thermodynamically stable [4 + 2] cycloadducts of lanthanum-encapsulated endohedral metallofullerenes

2014 ◽  
Vol 10 ◽  
pp. 714-721 ◽  
Author(s):  
Yuta Takano ◽  
Yuki Nagashima ◽  
M Ángeles Herranz ◽  
Nazario Martín ◽  
Takeshi Akasaka
Keyword(s):  
Thermal Stability ◽  
Material Science ◽  
Molecular Structures ◽  
Spectroscopic Methods ◽  
Dynamic Nmr ◽  
The Novel ◽  
Endohedral Metallofullerenes ◽  
Derivatives Of ◽  
Paramagnetic Properties

The [4 + 2] cycloaddition of o-quinodimethanes, generated in situ from the sultine 4,5-benzo-3,6-dihydro-1,2-oxathiin 2-oxide and its derivative, to La metal-encapsulated fullerenes, La2@C80 or La@C82, afforded the novel derivatives of endohedral metallofullerenes (3a,b, 4a,b and 5b). Molecular structures of the resulting compounds were elucidated using spectroscopic methods such as MALDI–TOF mass, optical absorption, and NMR spectroscopy. The [4 + 2] adducts of La2@C80 (3a,b, and 4a,b) and La@C82 (5b), respectively, retain diamagnetic and paramagnetic properties, as confirmed by EPR spectroscopy. Dynamic NMR measurements of 4a at various temperatures demonstrated the boat-to-boat inversions of the addend. In addition, 5b revealed remarkable thermal stability in comparison with the reported [4 + 2] cycloadduct of pentamethylcyclopentadiene and La@C82 (6). These findings demonstrate the utility of sultines to afford thermodynamically stable endohedral metallofullerene derivatives for the use in material science.

THIAZOLOISOQUINOLINES: I. THE SYNTHESIS OF THIAZOLO[4,5-c]ISOOUINOLINE

1966 ◽  
Vol 44 (21) ◽  
pp. 2465-2472 ◽  
Author(s):  
Catherine E. Hall ◽  
Alfred Taurins
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Hydrochloric Acid ◽  
Potassium Thiocyanate ◽  
Heterocyclic Ring ◽  
Ring System ◽  
Hydrogen Iodide ◽  
Red Phosphorus ◽  
Nucleophilic Displacement ◽  
Derivatives Of

Thiazolo[4,5-c]isoquinoline (I), a new heterocyclic ring system, has been synthesized from 3-aminoisoquinoline (II) in four steps by reaction with potassium thiocyanate and bromine to give 3-amino-4-thiocyanoisoquinoline (VII), cyclization with hydrochloric acid to yield 2-aminothiazolo[4,5-c]isoquinoline (VIII), Sandmeyer reaction to give 2-chlorothiazolo-[4,5-c]isoquinoline (IX), and finally reduction with hydrogen iodide and red phosphorus to yield I. The attempted preparation of I via 3-amino-4-bromoisoquinoline was unsuccessful. Various 2-substituted derivatives of I were prepared by nucleophilic displacement of the chlorine atom in 2-chIorothiazolo[4,5-c]isoquinoline. The nuclear magnetic resonance and ultraviolet spectra of I and some of its derivatives were studied.

Sign in / Sign up

Export Citation Format

Share Document