L- pyrrolidine

Methyl 6,8-dideoxy-6-(l-methyl-trans-4-propyl-L-pyrrolidin-2-ylcarbonylamino)-l-thio-D-erythro-D-galacto-octopyranoside... 

An example of double asymmetric induction has been reported. The resolved enantiomers of rac-4 have been converted to the aluminum enolates and reacted at —78 °C with enantiomer-ically pure ter/-butyl (S)-2-fonnyl-l-pyrrolidine carboxylate46. A comparison of the two reactions reveals that the reaction pair leading to the (5Fe,/ ,5)-product is matched while the alternative reaction pair is mismatched. 

In a related study, the reaction of the enamine, l,2-dihydro-3-(2-methoxymethyl-l-pyrrolidin-yl)naphthalene [from 3,4-dihydro-2(l//)-naphthalenonc and (S)-2-(methoxymethyl)pyrrolidine] with 2-aryl-l-nitroethenes gave, after hydrolysis, an 83 17 to 95 5 mixture of the (3S,YR)- and (1/ ,1 T )-nitro ketones31. 

They have developed direct asymmetric synthesis of quaternary carbon centers via addition-elimination process. The reactions of chiral nitroenamines with zinc enolates of a-substituted-8-lactones afford a,a-disubstituted-6-lactones with a high ee through addition-elimination process, in which (5)-(+)-2-(methoxy methy l)pyrrolidine (SMP) is used as a chiral leaving group (Eq. 4.96).119 Application of this method to other substrates such as a-substituted ketones, esters, and amides has failed to yield high ee. 

Oxopropionic acid 2-Oxo-l -pyrrolidine-propionitrile CH3C(=0)C02H 88.06 138.17 3, 608... 

The situation may be further complicated by the presence of different polymorphs for tris(l-pyrrolidine-dithiocarbamato)iron(III) two solvent-free modifications could be characterised. The first one has been crystallised from an ethanol/chloroform solution [14], whereas the second has been isolated from a chloroform/toluene mixture [16]. Both compounds differ in their structural parameters determined at room temperature, where they are both high spin. At lower temperatures the ethanol/chloroform product displays a gradual spin transition [14], whereas the chloroform/toluene form remains high spin down to very low temperature [33]. 

Chemical degradations have allowed the identification of both extremities of peripentadenine, hexanoic acid (present as an amide) and 2-hydroxy-6-meth-ylacetophenone. 13C NMR showed that the rest of the molecule included two nitrogen atoms, six methylenes, and one methine arranged in a (3-propylami-no)-l-pyrrolidine unit substituted at C-2. This formula was definitively proved by chemical degradations as well as by two total syntheses. As noted before in the cases of hygrine and of the ruspolinone alkaloids, peripentadenine is optically inactive. 

As a final example let us consider the anion [(PhN)2CN(CH2)4] (NN -diphenyl-l -pyrrolidine carbodiimide anion = [DPPC]-) illustrated in Scheme 15, which undergoes an irreversible oxidation at +0.8 V (vs. Ag/AgCl).111... 

H). C,8H34N206S. the first lincosaminide antibiotic to which a structure was assigned, is defined chemically as methyl 6,8-dideoxy-6-(l-methyl-fro/M-4-propyl-L-pyrrolidin-2-ylcarbonylamino)-l-thio-D-erythro-L>-gal-actu-octopyranoside. Both lincomycin and the semisynthetic clindamycin (I, R = H, R = Cl), CisH ClNjOsS, are widely used in clinical practice. The trivial name of the sugar fragment of this antibiotic, methyl a-thiolincosaminide, has lent itself to the other members of this family, whether produced as secondary metabolites of soil microorganisms or derived semisynthetically by chemical modification. 

Pyrrolidone is first reacted with sodium hydride, then with ethyl chloroacetate to give ethyl 2-oxo-l-pyrrolidine acetate. 

A solution of 0.3 mol of ethyl 2-oxo-l-pyrrolidine acetate in 300 ml of methanol, saturated with ammonia at 20° to 30°C, is heated at 40° to 50°C for 5 hours, while continuously introducing ammonia. The reaction mixture is evaporated to dryness and the residue recrystallized from isopropanol. 2-Oxo-1-pyrrolidineacetamide is obtained in a yield of 86%. MP 151.5° to 152.5°C. 

Fig. 13.34. Enders SAMP method for the generation of enantiomerically pure a-alky-Lated carbonyl compounds SAMP, (S)-aminoprolinol methyl ether = (5)-2-methoxymethyl-l-pyrrolidin-amine, or S-l-amino-2-(methoxymethyl)pyrrolidine (which is the name according to IUPAC rules).

A. The DADMe modification also provides a favorable charge localization to place the cation at the l -position. The pKa of l -pyrrolidine nitrogen in DADMe system is 8.575 and provides the cationic nitrogen to ion pair with phosphate in the active site of phosphorylases. The N4 nitrogen of Immucillin-H has a pKa of 6.972 and is cationic in the active site, however the Cl -C9 distance is only... 

Bromopbenyl)[2-trifluorometbyl-4-(trans-(2-((3-(l-pyrrolidin-2-onyl)-prop-l-ylamino)carbonyl)cycloprop-l-yl)pbenyl]sulfide... 

Methoxy 2-Trifluoromethyl 3-(l-pyrrolidin-2-only-prop-l-yl)amine 495... 

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