2628-66-2

Upstream product

• 17455-13-9 18-crown-6 ether 
• 736109-58-3 1,7,7-trimethyl-bicyclo[2.2.1]heptan-2-one 
• 119-26-6 (2,4-dinitro-phenyl)-hydrazine 
• 40920-05-6 (+/-)-2-(methylthio)-2-bornene 
• 464-49-3 (1R,4R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-one 
• 7519-74-6 (+/-)-thiocampher 
• 76-22-2 Camphor 
• 124666-33-7 rac-camphor thiosemicarbazone 
• 663197-88-4 (+/-)-5'-acetamido-3'-acetyl-1,7,7-trimethylspiroheptane-2,2'(3'H)-<1,3,4>thiadiazole> 

Relevant academic research and scientific papers

Thiofenchone S-methylide and its spiro-1,3,4-thiadiazoline precursor

Spiro[fenchane-2,2′-(1,3,4)-thiadiazoline] (6), prepared from thiofenchone and diazomethane, extrudes N2(t1/2 22 min, 46°C, toluene) and furnishes the S-methylide 7 which, in turn, closes the thiirane ring or else is intercepted by 1,3-cycloadditions to dipolarophiles (tetracyanoethylene, maleic anhydride, N-methyl-1,2,4-triazoline-3,5-dione, aromatic thioketones). When thiocarbonyl S-methylide 7 is set free in methanol, fenchone S,O-dimethylacetal is formed as an HX adduct. Catalysis by acetic acid converts 7 to 1-(methylthio)-α-fenchene (25) by way of a Wagner-Meerwein rearrangement. The addition of diazomethane to thiocampher leads, via thiadiazoline 12, to thiocamphor S-methylide; the latter undergoes a 1,4-H shift, thus affording 2-methylthio-2-bornene (11).

Acid-base reactions of adamantanethione S-methylide and its spiro-1,3,4-thiadiazoline precursor

The spiro-1,3,4-thiadiazoline 1 loses N2 at 45°C, and, as recently reported, the short-lived adamantanethione S-methylide (2) is an active 1,3-dipole. Interception of 2 by acids HX consists of CH2-protonation and ion recombination. Even 1 acts as HX vs 2 and - after electrocyclic ring opening of the anion (13 →15) - affords the dithioacetal C22H32N2S2 (14). The Δ3-thiadiazoline 1 is converted by base or acid catalysis to the Δ2-tautomer 21. Amidrazones (25, 26) are formed from 1 and sec-amines. The mechanisms are discussed and the structures elucidated.

Unexpected Transformations of Camphor (Thio)Semicarbazones under Acetylating Conditions

The formation of camphor mono- and diacetylhydrazones (1, 4, 6) and a stereoselective synthesis of the spirothiadiazoline (1R)-(+)-2 is described.The degradation of (thio)semicarbazones 3 (X = O, S) and diacetylhydrazone 4 to the acetylhydrazone 6 has bee

Complexes of Hydrazines with Crown Ethers and their Reaction with Carbonyl Compounds

The stable crystalline stoichiometric complexes 3-8 of mono- and di-substituted hydrazines with crown ether-type neutral ligands (1, 2), described for the first time, are utilized for the synthesis of the corresponding substituted hydrazones in lipophilic solvents by the reaction with carbonyl compounds under phase transfer conditions.