64439-31-2Relevant articles and documents
Synthesis of Terpineol from Alpha-Pinene Catalyzed by α-Hydroxy Acids
Hu, Yi-Ming,Huang, Xiao-Rui,Meng, Zhong-Lei,Qin, Rong-Xiu,Wen, Ru-Si,Zhou, Yong-Hong
, (2022/02/17)
We report the use of five alpha-hydroxy acids (citric, tartaric, mandelic, lactic and glycolic acids) as catalysts in the synthesis of terpineol from alpha-pinene. The study found that the hydration rate of pinene was slow when only catalyzed by alpha-hydroxyl acids. Ternary composite catalysts, composed of AHAs, phosphoric acid, and acetic acid, had a good catalytic performance. The reaction step was hydrolysis of the intermediate terpinyl acetate, which yielded terpineol. The optimal reaction conditions were as follows: alpha-pinene, acetic acid, water, citric acid, and phosphoric acid, at a mass ratio of 1:2.5:1:(0.1–0.05):0.05, a reaction temperature of 70? C, and a reaction time of 12–15 h. The conversion of alpha-pinene was 96%, the content of alpha-terpineol was 46.9%, and the selectivity of alpha-terpineol was 48.1%. In addition, the catalytic performance of monolayer graphene oxide and its composite catalyst with citric acid was studied, with acetic acid used as an additive.
Substrate flexibility and reaction specificity of tropinone reductase-like short-chain dehydrogenases
Reinhardt, Nicole,Fischer, Juliane,Coppi, Ralph,Blum, Elke,Brandt, Wolfgang,Draeger, Birgit
, p. 37 - 49 (2014/03/21)
Annotations of protein or gene sequences from large scale sequencing projects are based on protein size, characteristic binding motifs, and conserved catalytic amino acids, but biochemical functions are often uncertain. In the large family of short-chain dehydrogenases/reductases (SDRs), functional predictions often fail. Putative tropinone reductases, named tropinone reductase-like (TRL), are SDRs annotated in many genomes of organisms that do not contain tropane alkaloids. SDRs in vitro often accept several substrates complicating functional assignments. Cochlearia officinalis, a Brassicaceae, contains tropane alkaloids, in contrast to the closely related Arabidopsis thaliana. TRLs from Arabidopsis and the tropinone reductase isolated from Cochlearia (CoTR) were investigated for their catalytic capacity. In contrast to CoTR, none of the Arabidopsis TRLs reduced tropinone in vitro. NAD(H) and NADP(H) preferences were relaxed in two TRLs, and protein homology models revealed flexibility of amino acid residues in the active site allowing binding of both cofactors. TRLs reduced various carbonyl compounds, among them terpene ketones. The reduction was stereospecific for most of TRLs investigated, and the corresponding terpene alcohol oxidation was stereoselective. Carbonyl compounds that were identified to serve as substrates were applied for modeling pharmacophores of each TRL. A database of commercially available compounds was screened using the pharmacophores. Compounds identified as potential substrates were confirmed by turnover in vitro. Thus pharmacophores may contribute to better predictability of biochemical functions of SDR enzymes.
Synthesis and sweetness characteristics of L-aspartyl-D-alanine fenchyl esters
Yuasa,Nagakura,Tsuruta
, p. 5013 - 5018 (2007/10/03)
Four isomers of the L-aspartyl-D-alanine fenchyl esters were prepared as potential peptide sweeteners. L-Aspartyl-D-alanine (+)-α-fenchyl ester and L-aspartyl-D-alanine (-)-β-fenchyl ester showed sweetness with potencies 250 and 160 times higher than that of sucrose, respectively. In contrast, L-aspartyl-D-alanine (+)-β-fenchyl ester and L-aspartyl-D-alanine (-)-α-fenchyl ester had the highest sweetness potencies at 5700 and 1100 times that of sucrose, respectively. In particular, L-aspartyl-D-alanine (-)-α-fenchyl ester had an excellent sweetness quality, but L-aspartyl-D-alanine (+)-β-fenchyl ester did not have an excellent quality of sweetness because it displayed an aftertaste caused by the strong sweetness.
