Phenylcyclopropane carboxylic acids

Tranylcypromine Tranylcypromine, ( )-lran5-2-phenylcyclopropylamine (7.2.10), differs from the drugs described above in that it is not a derivative of hydrazine. It is synthesized from the ethyl ester of 2-phenylcyclopropan carboxylic acid (7.2.7), which... 

The data in Table 2 show that the rotations of cis-substituted cyclopropanes are often considerably smaller than those of the corresponding trans compounds. If the cyclopropane bears a phenyl ring the relationship between the magnitude of the rotations of cis and trans compounds is not obvious. For instance, the rotation of the cis-phenylcyclopropane carboxylic acid 23 is small compared with the rotation of the trans compound 22 and also the rotation of the cis-phenylcyclopropane 32 is rather small. On... 

A nice complement to the Haller-Bauer reaction (Section II.B) is the decarbonylation of aldehydes with (Ph3P)3RhCl (Wilkinson s catalyst) A recent example comes from the work of Baldwin and Barden and is shown in Figure 5. Interestingly, partial optical resolution was achieved in this synthesis by use of an optically active copper catalyst for the preparation of the labeled phenylcyclopropane carboxylic acid. The resolution to optical purity was then accomplished by recrystallization of the quinine salt of the acid. 

A method which avoids the use of hydrazides has been described by Weinstock " who demonstrated that mixed anhydrides interact with sodium azide in excellent yield. Thus the mixed anhydride (53) obtained from 2-phenylcyclopropane carboxylic acid and ethyl chloroformate is converted to the azide (54) after treatment for 30 minutes at 0° with sodium azide in aqueous acetone. It has been... 

Exceptional are cyciopropanations with phenylethenyl-substituted diazoacetate 6 bearing a (R)-pantolactone unit as chiral auxiliary. The optimized rhodium(II)-catalyzed reaction of this diazo compound with phenylethene provides the cyclopropanecarboxylate 7 with a d.r. of 98.5 1.5. Recrystallization affords diastereomerically pure 7 which can be transformed into the enantiomerically pure (1 /< .2R )-1-amino-2-phenylcyclopropane carboxylic acid. Use of the corresponding (S)-lactates allows entry into the enantiomeric series105. This method was also applied to the enantioselective preparation of tropanes106... 

Triethylamine in acetone added at 0° to a soln. of ci5-2-phenylcyclopropane-carboxylic acid in water-acetone, then a soln. of ethyl chloroformate in acetone added slowly at the same temp., stirred 30 min. at 0°, aq. Na-azide added drop-wise, stirred 1 hr. at 0°, poured into excess ice water, the resulting crude acid azide rearranged in toluene at steam bath temp., the isocyanate suspended in aq. 20%-HGl, and refluxed 9 hrs. cis-2-phenylcyclopropylamine. Y 77%.— Mixed anhydrides react with Na-azide under very mild conditions to form acid azides in excellent yield. The method avoids prepn. of the acid chloride preventing isomerization to the trans-isomer. J, Weinstock, J. Org. Ghem. 26, 3511 (1961). 

In the VCD spectra of mws-2-phenylcyclopropane carboxylic acid and similar compounds, the symmetrical stretching vibration of the methylene group of the cyclopropane ring always showed a negative sign for the (IR, IR) configuration. 

A solution of the above ester (207.8 grams) and 64.5 grams of sodium hydroxide in 80 cc of water and 600 cc of ethanol is refluxed for 9 hours. The carboxylic acid of 2-phenylcyclopropane is liberated with 200 cc of concentrated hydrochloric acid. The 2-phenylcyclopropanecarboxylic acid contains 3 to 4 parts of the trans isomer to 1 part of the cis isomer. The acid is recrystallized from hot water. The pure trans isomer comes out as crystalline material (solid) while the cis isomer stays in solution. 

C10H10 2-methytindene 2177-47-1 25.00 1.1522 2 19143 C10H1002 trans-2-phenylcyclopropane-1 -carboxylic acid 939-90-2 27.69 1.0799 2... 

Koyanag and coworkers have determined the relative acidities of the cis/trans isomeric phenylthiocyclopropanecarboxylates 245 and 246, respectively, as compared to phenylcyclopropane carboxylate (247). H/D exchange experiments have shown that the ester 245 is 18.4 and 246 is 8.0 times more acidic than 247. Thus, a cis-phenylthio group stabilizes a negative charge much better than, for example, a phenyl group. 

In related syntheses of aminocyclopropylcarboxylic acids and acid derivatives, different combinations of protecting groups have been employed and among the compounds made were carnosadine (8), ( + )-2,3-methano-5-oxoproline (9), ( + )-2,3-methanoproline (10), /rani-l-benzoylamino-2-phenylcyclopropane-l-carboxylic acid (11) (and variants with substituted phenyl and thiophene) tra i-l-amino-2-isopropylcyclopropane-l-carboxylic acid (12) and coronamic acid (13). ... 

Both trans- and c/j-2-phenylcyclopropanecarboxylic acid (6) can also be decarboxylated with lead tetraacetate in benzene at 80 C in the presence of a catalytic amount of pyridine and copper(II) acetate to give rran. -l,2-diphenylcyclopropane (8) in low yield (18-22%). When the oxidative decarboxylation of these carboxylic acids is carried out with lead tetraacetate in the presenee of iodine under irradiation ra ,v-l-iodo-2-phenylcyclopropane (9) is obtained as the sole product in 43% yield. Under identical conditions 2,2-diphenylcyclopropanecarboxylic acid leads to 2-iodo-l,l-diphenylcyclopropane (mp 45.5 C) in 57% yield. 

Cyclopropane-1,1-dicarboxylic acid (30a) reacted with hydrobromic acid to (2-bro-moethyl)malonic acid (31a) . In a similar reaction, ethyl 1-acetylcyclopropane-l-carboxylate (31b) ( C enriched) was converted to 5-bromopentan-2-one upon treatment with hydrobromic acid and decarboxylation." In 2-benzoyl-3-phenylcyclopropane-1,1-dicarboxylic acid (31c), two different activating functions are present and can influence the addition of hydrogen bromide. In fact, products arising from the cleavage of either bond that link the phenyl-substituted carbon were isolated. Both primary products had lost hydrogen bromide and carbon dioxide. 

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