Amide trans

NHase from Rhodococcus. sp. AJ270 was isolated, purified, and applied to the enantiose-lective transformation of a series of cyclopropane carbonitriles. Amides with moderate ee were isolated from conversion of many of the cyclopropane substrates, to yield the amides trans-( IR, 2/ )-3-phenylcyclopropane carbonitrile (49% conv. 22.7% ee), trans-( IS, 35)-2,2-dimethyl-3-phenylcyclopropanecarbonitrile (40% conv. 84.7% ee), trans-( IR, 3/f)-2,2-dibromo-3-phenylcy-clopropanecarbonitrile (11.6% conv. 83.8% ee), cis-( IR, 25)-3-phenylcyclopropanecarbonitrile (25.8% conv. 95.4% ee), and cis-(lR, 2S )-2,2-dimethyl-3-phenylcyclopropanecarbonitrile (7.9% conv. 3.2% ee) [43],... 

The oxidative addition can take place from the top of the molecule (as shown), but it can also take place from the bottom, giving another diastereomeric intermediate that probably does not undergo migration. The two oxidative additions require rotations in opposite directions of the substrate with respect to the rhodium phosphine complex. The rotation required also depends on the geometrical isomer of the rhodium complex to be formed (alkene/amide trans or cis to phosphine here we have chosen an amide cis to both phosphorus atoms). Both the major and the minor diastereomeric substrate complex require such a rotation upon oxidative addition. 

Secondary amides trans- form) (solid phase) 1570-1515 6.37-6.60 s w... 

Secondary amides (trans- form) 1305-1200 7.67-8.33 w-m s Amide 111 band, usually at 1260cm" ... 

If alkyl groups are attached to the ylide carbon atom, cis-olefins are formed at low temperatures with stereoselectivity up to 98Vo. Sodium bis(trimethylsilyl)amide is a recommended base for this purpose. Electron withdrawing groups at the ylide carbon atom give rise to trans-stereoselectivity. If the carbon atom is connected with a polyene, mixtures of cis- and rrans-alkenes are formed. The trans-olefin is also stereoseiectively produced when phosphonate diester a-carbanions are used, because the elimination of a phosphate ester anion is slow (W.S. Wadsworth, 1977). 

Aryl- or alkenylpalladium comple.xcs can be generated in situ by the trans-metallation of the aryl- or alkenylmercury compounds 386 or 389 with Pd(Il) (see Section 6). These species react with 1,3-cydohexadiene via the formation of the TT-allylpalladium intermediate 387, which is attacked intramolecularlv by the amide or carboxylate group, and the 1,2-difunctionalization takes place to give 388 and 390[322]. Similarly, the ort/trt-thallation of benzoic acid followed by transmetallation with Pd(II) forms the arylpalladium complex, which reacts with butadiene to afford the isocoumarin 391, achieving the 1,2-difunctionalization of butadiene[323]. 

Alkyne Sodium Ammonia Trans alkene Sodium amide ... 

AMIDES, FATTY ACID] (Vol 2) trans-ll-Octadecenoic acid [693-72-1]... 

Fig. 8. Rephcation. The amino adenosine X and the pentafluorophenyl ester Y form a hydrogen-bonded dimer XY, prior to reaction between the amine and the activated ester groups (shown in the circle). The reaction product is a <7 -amide conformer cis-Z that isomeri2es to the more stable trans- acnide Z. The rephcative process is cataly2ed by the reaction product Z (also referred to as the template). First, a termolecular complex XYZ is formed from X, Y, and Z.

The two methyl groups are not equivalent at 303 K (3 = 2.86 and 3.14), rotation about the CN bond is frozen, because this bond has partial tt character as a result of the mesomerlc (resonance) effects of the dimethylamino group (+Af) and of the aldehyde function (-M), so that there are cis and trans methyl groups. Hence one can regard 3-(A(A -dlmethylamlno)acrolein as a vinylogue of dlmethylformamide and formulate a vlnylogous amide resonance. 

MonofluoToalkanes and vicinal difluoroalkanes are dehydrofluonnated if strong enough bases are applied [10 12] In 5-fluorononane and fluorocyclodo-decane, elimination by means of sodium methoxide in methanol gives cis- and trans allcenes in respective yields of 8 and 21% and in ratios of 1 2 2 2 4, however, the bulky lithium diisopropyl amide m tetrahydrofuran produces trdns-isomers almost exclusively The strength of the base does not have much effect on the rate of elimination, but the lithium cation causes considerable acceleration [10] (equation 10)... 

Consider a nucleus that can partition between two magnetically nonequivalent sites. Examples would be protons or carbon atoms involved in cis-trans isomerization, rotation about the carbon—nitrogen atom in amides, proton exchange between solute and solvent or between two conjugate acid-base pairs, or molecular complex formation. In the NMR context the nucleus is said to undergo chemical exchange between the sites. Chemical exchange is a relaxation mechanism, because it is a means by which the nucleus in one site (state) is enabled to leave that state. 

Aromatic enamines were prepared by dehydroha logenation of /3-bromo-amines with strong base. While trans enamines were thus formed, one obtained mostly cis enamines from rearrangement of the corresponding allylic amines under similar reaction conditions (646). Vicinal endiamines were obtained from S-dichloroamines and lithium amides (647). 

FIGURE 5.2 The peptide bond is shown in its usnal trans conformation of carbonyl O and amide H. The atoms are the oi-carbons of two adjacent amino acids joined in peptide linkage. The dimensions and angles are the average valnes observed by crystallographic analysis of amino acids and small peptides. The peptide bond is the light gray bond between C and N. (Adapted from Ramachandran, G. A., ct ai, 1974. Biochimica Biophysica Acta 359 298-302.)... 

In this series of amides, hydrolysis or aminolysis of a simple ester, cleavage of a silyl groups a cis/trans isomerization, or reduction of a quinone to a hydro-quinone exposes an alcohol that then induces deprotection by intramolecular addition to the amide carbonyl. 

Condensation of m-fluorobenzaldehyde with malonic acid leads to the trans cinnamic acid 96 acylation of the acid chloride with cyclopropylaminc leads to amide 97 (cinflumide), a muscle relaxant [24]. 

Rolgamidine (14) is a dihydropyrrole derivative which has antidiarrheal activity It can be synthesized by alkylation of trans 2,5-dimethyl-3 pyrroline (12) with methyl bromoacefate to give 13 An amide-ester exchange reaction with guanidine hydrochloride completes the synthesis of rolgamidine (14) [3]... 

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