Di-p-toluoyl-L-tartaric acid

The filtrate of the salt formation and the filtrate of the first recrystallization were combined. After evaporation under vacuo and treatment of the residue with NaOH solution gave impure (-)-amine. This amine (2.0 g), 3.2 g (-)-di-p-toluoyl-L-tartaric acid and 400 mL of methanol was heated to solution. According to the procedure as described above, 1.3 g (28.4 %) of (-)-13.HCl was obtained with (mp 113-114 °C) [a] = - 62.5°. 

Dithiocyclohexane-2-thione, 441 Di-p-toluoyl-L-tartaric acid, 213 Di-(2,2,2-trichloroethyl)phosphoro-... 

Treatment of 20 with dimethyl carbonate led to carbamate 21, which was reduced by hydrogenation over 5% Rh/C to afford the corresponding piperidine 22 as a 17 1 mixture of cis trans diastereomers. A reductive amination using benzaldehyde provided 23 as the hydrochloride salt. The carbamate was reduced with LAH and resolved with di-p-toluoyl-L-tartaric acid to provide the DPTTA salt of 14. 

The absolute configuration of natural l-( -f- )-laudanosine was determined by chemical correlation with l-( — )-iV-norlaudanosine (LXXVI) whose configuration was established by oxidative degradation. Resolution of racemic LXXVI with V-acetyl-L-Ieucine gave the levorotatory base [oil, bp 210° [a]j> —13.3° in EtOH —21° in CHCI3 B HCl, mp 167° [a]i) -f 38° in H2O]. From the mother liquors the enantiomer was obtained by using di-p-toluoyl-L-tartaric acid -1-13° —21°). 

R,5,S)-l-Allyl-2,5-dimethylpiperazine has been prepared by direct enantiospecific synthesis [29,39] and via classical resolution of the racemic piperazine [23,29]. Kilo-scale batches of (-)-(2R,55)-l-allyl-2,5-dimethylpi-perazine have been prepared from tra s-2,5-dimethylpiperazine by the three-step monoallylation shown in Scheme 5, followed by a resolution using di-p-toluoyl-D-tartaric acid. This resolution has also been achieved in a two-stage process using (—)-camphoric acid followed by di-p-toluoyl-D-tartaric acid, giving (—)-(22 ,5S)-l-allyl-2,5-dimethylpiperazine in >99% optical purity. 

Bagi P, Kdllay M, Hessz D, Kubinyic M, Holczbauer T, Czugler M, Fogassy E, Keglevich G (2014) Resolution of l-n-propoxy-3-methyl-3-phospholene 1-oxide by diastereomeric complex formation using TADDOL derivatives and calcium salts of O, 0 -dibenzoyl-(2R,3R)-or O, 0 -di-P-toluoyl-(2R,3R)-tartaric acid. Tetrahedron Asymmetry 25 318-326... 

Resolution of l- -propo5y-3-methyl-3-phospholene 1-oxide (754) using TADDOL derivatives (755) or Ca salts of 0,0 -dibenzoyl-(2R,3R)- (756a) or 0,0 -di-p-toluoyl-(2R,3)-tartaric acid (756b) has been developed (Scheme 212). Both antipodes of l-n-propo qr-3-phos-pholene 1-oxide (754) have been obtained with ee >96% by exploiting the different antipode preference of the TADDOL derivatives (755). The absolute configuration of the 3-phospholene oxide (754) enantiomers has been determined by CD spectroscopy, assisted by TD-DFT quantum chemical calculations. Moreover, it has been found that the solvent used for resolution had a significant effect on the efficiency of the resolutions. ... 

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