Synthesis of the Novel Ring Systems 1,2,3,4-Oxazadisiletidine and 1,3,4,2,5-Dioxazadisilolidine

1989 ◽  
Vol 28 (1) ◽  
pp. 54-55 ◽  
Author(s):  
Gregory R. Gillette ◽  
Jim Maxka ◽  
Robert West
Keyword(s):  
The Novel ◽  
Ring Systems

Synthesis and Thermolysis of the Novel Ring Systems Containing Nitrogen and Tetracoordinate Selenium

2001 ◽  
Vol 168 (1) ◽  
pp. 259-262 ◽  
Author(s):  
Naokazu Kano ◽  
Yuya Daicho ◽  
Nobuhito Nakanishi ◽  
Takayuki Kawashima
Keyword(s):  
The Novel ◽  
Ring Systems

Chemistry of the Podocarpaceae. LXXII. Ring-C Modifications of Totarol

1988 ◽  
Vol 41 (8) ◽  
pp. 1171 ◽  
Author(s):  
RC Cambie ◽  
GR Clark ◽  
CEF Rickard ◽  
PS Rutledge ◽  
GR Ryan ◽  
...  
Keyword(s):  
Single Crystal ◽  
High Yield ◽  
The Novel ◽  
X Ray Diffraction ◽  
Lithium Iodide ◽  
Rearrangement Product ◽  
Ring Systems ◽  
X Ray ◽  
Naturally Occurring

Totarol (1) has been converted into conjugated dienolides which have the B/C-ring systems found in naturally occurring nagilactones A and C and their analogues. Thus, treatment of the epoxide (11) with titanium(IV) tetrachloride affords the desired 7,9(11)- diene (12) and the saturated γ- lactone (23). Treatment of the epoxide (11) with diazabicyclo [3.4.0]non-5-ene gives a high yield of the butenolide (24); the alcohol (25) has been shown to be an intermediate in this reaction. Treatment of (11) with lithium iodide dihydrate in collidine gives the butenolides (24) and (26), and the novel rearrangement product (27) which is slowly converted on standing into the epoxide (29). Treatment of (11) with anhydrous lithium iodide gives the α- pyrone (30). The structures of compounds (11), (23), (24) and (29) have been determined by single-crystal X-ray diffraction measurements.

Synthesis of Spiro[cycloalkane-pyridazinones] with High Fsp3 Character Part 2.*

2020 ◽  
Vol 17 ◽  
Author(s):  
Csilla Sepsey Für ◽  
Eszter Judit Horváth ◽  
Áron Szigetvári ◽  
Miklós Dékány ◽  
László Hazai ◽  
...  
Keyword(s):  
Physicochemical Parameters ◽  
Building Blocks ◽  
Drug Candidate ◽  
Magnesium Bromide ◽  
Grignard Reaction ◽  
The Novel ◽  
Compound Library ◽  
Ring Systems ◽  
Aromatic Systems

Abstract: An extended compound library of spiro[cycloalkane-pyridazinones] with high Fsp3 character is targeted. There are two possibilities to improve the physicochemical parameters of a drug candidate molecules or building blocks, either to replace the aromatic systems with bioisoster heteroaromatic moieties, e.g. with one or two nitrogen containing ring systems (pyridines, pyridazines, pyrimidines, etc.), or to increase the Fsp3 character of the compounds. Using a new synthetic ap-proach, the Grignard reaction of 2-oxaspiro[4,5]decane-1,3-dione and 2-oxaspiro[4,4]nonane-1,3-dione with p-halophenyl- or p-alkylphenyl-magnesium bromide resulted in the formation of the corresponding 2-oxoethyl-cycloalkanecarboxylic ac-ids, which served as starting materials for the formation of pyridazinone with hydrazine or phenylhydrazine. The pyridazi-nones obtained were alkylated with methyliodide or benzylbromide. 16 Novel 4-tolyl- or 4-halophenyl-2,3-diazaspiro[5.5]undec-3-en-1-one and 4-tolyl- or 4-halopyhenyl-7,8-diazaspiro[4.5]dec-8-en-6-one, and their N-methyl, N-benzyl, and N-phenyl derivatives were synthetized.The physicochemical parameters and the Fsp3 character of the novel compounds obtained were studied. A few of them showed excellent logP and clogP values, but introduction of further phe-nyl group seemed to be disadvantageous

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