The Stereochemistry of the Reformatsky Reaction of Methyl 4-Bromo-3-methylbut-2-enoate with β-Cyclocitral and Related Compounds

1975 ◽  
Vol 53 (13) ◽  
pp. 1943-1948 ◽  
Author(s):  
R. N. Gedye ◽  
Parkash Arora ◽  
A. H. Khalil
Keyword(s):  
Wittig Reaction ◽  
Main Product ◽  
Reformatsky Reaction ◽  
Reformatsky Reactions ◽  
Hydrolysis Of ◽  
Related Compounds ◽  
The Reformatsky Reaction

Both methyl Z- and E-4-bromo-3-methylbut-2-enoate react with β-cyclocitral in the presence of zinc to give the δ-lactone of 5-hydroxy-3-methyl-5-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2-pentenoic acid as the main product, indicating an E to Z inversion during the Reformatsky reaction. Similar results were obtained in the Reformatsky reactions of the Z- and E-bromo-esters with benzaldehyde and cyclohexenecarboxaldehyde. Here hydrolysis of the Reformatsky product gave, in each case, the corresponding Z-2,E-4-acids as the main products, indicating the formation of the δ-lactone as an intermediate. The synthesis of Z- and E-β-ionylideneacetic acid and the corresponding ring demethyl analogs using a Wittig reaction is also described.

Catalytic enantioselective Reformatsky reactions

2008 ◽  
Vol 80 (5) ◽  
pp. 891-901 ◽  
Author(s):  
Pier Giorgio Cozzi ◽  
Alessandro Mignogna ◽  
Luca Zoli
Keyword(s):  
Organic Synthesis ◽  
Chiral Auxiliary ◽  
Chiral Ligands ◽  
Reformatsky Reaction ◽  
Asymmetric Transformations ◽  
Stoichiometric Amount ◽  
General Finding ◽  
Reformatsky Reactions ◽  
The Reformatsky Reaction

The Reformatsky reaction is a venerable named reaction that was introduced more than 120 years ago. Diastereoselective variants based on the use of chiral auxiliary and enantioselective protocols, based on the employment of stoichiometric amount of chiral ligands, have been successfully applied in organic synthesis during the years. However, a facile and general catalytic enantioselective variant was still a difficult task. Recently, we have established a new general and straightforward methodology for catalytic enantioselective Reformatsky reaction based on different concepts. In this paper, we present our general finding in catalytic enantioselective Reformatsky reaction of ketones, imines, and aldehydes. Our simple methodologies could become benchmark reactions for testing new synthesized chiral ligands for asymmetric transformations.

Dibenzo[b,f]thiepin-10-carbonitrile, its 10,11-dihydro derivative, some transformation products and related compounds

1983 ◽  
Vol 48 (4) ◽  
pp. 1187-1211 ◽  
Author(s):  
Karel Šindelář ◽  
Jiří Holubek ◽  
Miroslav Ryska ◽  
Emil Svátek ◽  
Jiří Urban ◽  
...  
Keyword(s):  
Main Product ◽  
Cardiovascular Effects ◽  
Transformation Products ◽  
Anticonvulsant Effect ◽  
Cuprous Cyanide ◽  
High Doses ◽  
Hydrolysis Of ◽  
Related Compounds ◽  
By Products ◽  
Dichloro Derivative

Reactions of 10-bromodibenzo[b,f]thiepin (IIIa), its 2-chloro derivative IIIb and 2,8-dichloro derivative IIIc with cuprous cyanide in boiling dimethylformamide gave the carbonitriles Iabc out of which the first two were reduced with sodium borohydride to the 10,11-dihydro derivatives IVab; the amides VIIab were obtained as by-products. Alkaline hydrolysis of the nitriles IVab or their mixtures with the amides VIIab afforded the acids VIIIab. By the addition of 3-dimethylaminopropylmagnesium chloride to the nitrile Ia cis and trans-11-(3-dimethylaminopropyl)-10,11-dihydrodibenzo[b,f]thiepin-10-carbonitriles (XVIII) were obtained. Alkylation of the nitrile IVa with 2-dimethylaminoethyl chloride and 3-dimethylaminopropyl chloride resulted in the 10-(dimethylaminoalkyl) derivatives XX and XXI. A reaction of the crude cyano alcohol XXIII with phosphorus tribromide afforded the 2-bromoethyl derivative XXIV as a by-product only. The main product was the hydrobromide of the spirocyclic imidate XXX which affords by acid hydrolysis the spirocyclic lactone XXXI. An analogous sequence proceeding via the ether XXVI and the alcohol XXVII leads to the 10-(3-bromopropyl) derivative XXVIII as the main product. An attempt at preparing the same substance by alkylation of the nitrile IVa with 1,3-dibromopropane gave stereoisomeric dinitriles XXXII. At high doses the amides VIIab reveal an anticonvulsant effect, the acids VIIIab antiinflammatory actions, the basic nitrile cis-XVIII antireserpine activity and the basic nitriles XX and XXI a central depressant and pseudo-analgesic activity in addition to further peripheral and cardiovascular effects.

11-(Dimethylaminoalkyl)-6,11-dihydrodibenzo[b,e]thiepin-11-carbonitriles and some related compounds

1983 ◽  
Vol 48 (7) ◽  
pp. 1898-1909 ◽  
Author(s):  
Karel Šindelář ◽  
Jiří Holubek ◽  
Miroslav Ryska ◽  
Emil Svátek ◽  
Jiří Urban ◽  
...  
Keyword(s):  
Amino Acid ◽  
Potassium Hydroxide ◽  
Main Product ◽  
Sodium Hydride ◽  
Neurotropic Activity ◽  
Amide Hydrolysis ◽  
Hydrolysis Of ◽  
Related Compounds ◽  
Benzyltriethylammonium Chloride ◽  
Sodium Amide

The title compounds II and III were obtained by alkylations of 6,11-dihydrodibenzo[b,e]thiepin-11-carbonitrile (I) with 2-dimethylaminoethyl chloride and 3-dimethylaminopropyl chloride in the presence of sodium hydride or sodium amide. Hydrolysis of the nitrile II with potassium hydroxide in ethanol resulted in a small amount of the amino acid X and in the amine XI as the main product. Alkylations of I with 1,2-dibromoethane and 1,3-dibromopropane in the presence of sodium hydride gave the bromoalkylnitriles IV and V and the alkylenebisnitriles XIII and XIV. The preparation of the methylpiperazinopropyl derivative VI proved the usefulness of compounds IV and V in the synthesis of further aminonitriles of this series. Alkylation of the nitrile I with 1,2-dibromoethane in the presence of sodium hydroxide or potassium carbonate and benzyltriethylammonium chloride afforded three isomeric nitriles C17H13NS: the vinyl derivative IX, the 6,11-ethano-6H, 11H-dibenzo[b,e]thiepin derivative XV and finally the 1a,11b-dihydro-1H,7H-dibenzo[b,f]cyclopropa[d]thiocin derivative XVI. Compounds II, III, VI and XII showed some spasmolytic effects but their central neurotropic activity is insignificant.

Synthesis and Tautomerism of Curcumin Derivatives and Related Compounds

2015 ◽  
Vol 68 (2) ◽  
pp. 224 ◽  
Author(s):  
Hiroyasu Taguchi ◽  
Daijiro Yanagisawa ◽  
Shigehiro Morikawa ◽  
Koichi Hirao ◽  
Nobuaki Shirai ◽  
...  
Keyword(s):  
Parent Compound ◽  
Amyloid Plaques ◽  
Enol Form ◽  
19F Nmr ◽  
Enolic Form ◽  
Curcumin Derivatives ◽  
Alkyl Groups ◽  
Alzheimer Brain ◽  
Hydrolysis Of ◽  
Related Compounds

1,7-Bis(4′-hydroxy-3′-trifluoromethoxyphenyl)-1,6-heptadiene-3,5-dione (2a), related to curcumin, and thirteen 4-substituted derivatives were prepared and their keto/enol ratio in DMSO[D6] was determined by 19F NMR because the enolic form of these related curcumins had been shown to bind to amyloid plaques in the Alzheimer brain. The parent compound and the 4-ethoxycarbonyl derivative were almost 100 % in the enolic form that contains a conjugated hepta-1,4,6-trien-3-on-5-ol backbone. Enolisation decreased to varying amounts in the derivatives that had 4-substituted alkyl groups. Attempts to prepare the 4-hydroxypropyl derivative by hydrolysis of O-methoxymethyl 2m or O-tetrahydropyranyloxy 2n protected derivatives led to cyclised products. A related pyrimidine compound 6b that mimicked a fixed enol form was also prepared.

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