The aza-MBH reaction of imines 1 and beta-naphthyl acrylate 2 in the presence of C-6' modified beta-isocupreidine derivative 1c (0.1 equiv) and beta-naphthol 5 (0.1 equiv) afforded the corresponding (3S)-aza-MBH adducts 4 in high yield and excellent enantiomeric excess. These catalytic conditions allowed the aliphatic imines to be employed for the first time as electrophilic partners of the aza-MBH reaction. The coexistence of two H-bond donors with different acidic strengths was found to be crucial for the observed high enantioselectivity.
The beta-ICD (1a) or beta-ICD-amide (1e)-catalyzed aza-Morita-Baylis-Hillman reaction between N-sulfonylimines 3 and alkyl vinyl ketones 4 produced the (R)-enriched adducts 5. By adding a catalytic amount of beta-naphthol (2a), the enantioselectivity of the same reaction was inversed leading to (S)-5 in excellent yields and enantioselectivities. Both aromatic and aliphatic imines are accepted as substrates for this reaction.
The bifunctional catalyst 6'-deoxy-6'-acyl-A C H T U N G T R E N N U N G amino-b-isocupreidine (1) served both as a base to trigger the in situ generation of N-sulfonylimine from readily available a-amidosulfones and as a chiral nucleophile to initiate the enantioselective aza-Morita-Baylis-Hillman (aza-MBH) reaction. aMethylene-b-amino-b-alkyl carbonyl compounds, difficultly accessible previously, can now be synthesized in excellent yields and enantioselectivities.
There are twenty-five published structures of Mycobacterium tuberculosis anthranilate phosphoribosyltransferase (Mtb-AnPRT) that use the same crystallization protocol. The structures include protein complexed with natural and alternative substrates, protein:inhibitor complexes, and variants with mutations of substrate-binding residues. Amongst these are varying space groups (i.e. P21, C2, P21212, P212121). This article outlines experimental details for 3 additional Mtb-AnPRT:inhibitor structures. For one protein:inhibitor complex, two datasets are presented – one generated by crystallization of protein in the presence of the inhibitor and another where a protein crystal was soaked with the inhibitor. Automatic and manual processing of these datasets indicated the same space group for both datasets and thus indicate that the space group differences between structures of Mtb-AnPRT:ligand complexes are not related to the method used to introduce the ligand.
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