3663-79-4Relevant academic research and scientific papers
A short entry to enantiopure 2-substituted 1,4-benzodioxanes by efficient resolution methods
Bolchi, Cristiano,Fumagalli, Laura,Moroni, Barbara,Pallavicini, Marco,Valoti, Ermanno
, p. 3779 - 3785 (2003)
(R)-1,4-Benzodioxane-2-carboxilic acid (R)-1 was obtained by resolution of the racemic acid 1 with stoichiometric or nonstoichiometric (+)- dehydroabietylamine (+)-2 in high chemical yield and enantiomeric excess. (S)-1 was isolated from the mother liquors of the crystallisation of (R)-1·(+)-2 and its enantiomeric excess maximised by recrystallisation procedures involving a precipitation under kinetic control or, alternatively, by conversion into the methyl ester followed by a single crystallisation. The different mechanisms of the two S enrichments is well explained by the binary phase diagrams of the acid and of the ester, which show that the former is a racemic compound, whereas the latter a conglomerate. The DSC analyses were extended to 2-hydroxymethyl- and 2-mesyloxymethyl-1,4-benzodioxane, establishing that the alcohol forms a racemic compound, while its mesyl ester a conglomerate. On the basis of these results, different resolution strategies can be designed to obtain useful homochiral 2-substituted 1,4-benzodioxanes coupling the resolution of 1 via diastereomeric salt formation with the enantiomeric enrichments by recrystallisations, preferably of its conglomerate forming derivatives.
Enantioselective Access to Chiral 2-Substituted 2,3-Dihydrobenzo[1,4]dioxane Derivatives through Rh-Catalyzed Asymmetric Hydrogenation
Yin, Xuguang,Huang, Yi,Chen, Ziyi,Hu, Yang,Tao, Lin,Zhao, Qingyang,Dong, Xiu-Qin,Zhang, Xumu
supporting information, p. 4173 - 4177 (2018/07/29)
Rh-catalyzed asymmetric hydrogenation of various benzo[b][1,4]dioxine derivatives was successfully developed to prepare chiral 2-substituted 2,3-dihydrobenzo[1,4]dioxane derivatives using ZhaoPhos and N-methylation of ZhaoPhos ligands with high yields and excellent enantioselectivities (up to 99% yield, >99% enantiomeric excess (ee), turnover number (TON) = 24 000). Moreover, this asymmetric hydrogenation methodology, as the key step with up to 10 000 TON, was successfully applied to develop highly efficient synthetic routes for the construction of some important biologically active molecules, such as MKC-242, WB4101, BSF-190555, and (R)-doxazosin·HCl.
From 2-aminomethyl-1,4-benzodioxane enantiomers to unichiral 2-cyano- and 2-carbonyl-substituted benzodioxanes via dichloroamine
Bolchi, Cristiano,Valoti, Ermanno,Straniero, Valentina,Ruggeri, Paola,Pallavicini, Marco
, p. 6732 - 6737 (2014/08/05)
2-Substituted 1,4-benzodioxanes, such as 2-cyano-, 2-methoxycarbonyl-, 2-aminocarbonyl-, and 2-formyl-1,4-benzodioxane, are key synthons that for the most part are never described as enantiomers or are inadequately characterized for enantiomeric purity. They were prepared by quantitative N,N-dichlorination of (R)- and (S)-2-aminomethyl-1,4-benzodioxane and successive functional group conversions in high yields without any racemization of the stereogenic benzodioxane C(2).
Synthesis and biological evaluation of a series of benzoxazole/ benzothiazole-containing 2,3-dihydrobenzo[b][1,4]dioxine derivatives as potential antidepressants
Wang, Songlin,Chen, Yin,Zhao, Song,Xu, Xiangqing,Liu, Xin,Liu, Bi-Feng,Zhang, Guisen
supporting information, p. 1766 - 1770 (2014/04/17)
A series of benzoxazole/benzothiazole-2,3-dihydrobenzo[b][1,4]dioxine derivatives (5a-5d and 8a-8j) was synthesized. Compounds were evaluated for binding affinities at the 5-HT1A and 5-HT2A receptors. Antidepressant activities of the compounds were screened using the forced swimming test (FST) and the tail suspension test (TST). The results indicated that the compounds exhibited high affinities for the 5-HT1A and 5-HT2A receptors and showed a marked antidepressant-like activity. Compound 8g exhibited high affinities for the 5-HT1A (Ki = 17 nM) and 5-HT2A (Ki = 0.71 nM) receptors; it also produced a decrease of the immobility time and exhibited potent antidepressant-like effects in the FST and TST in mice.
Chemoenzymatic synthesis of piperoxan, prosympal, dibozane, and doxazosin
Rouf, Abdul,Gupta, Pankaj,Aga, Mushtaq A.,Kumar, Brijesh,Chaubey, Asha,Parshad, Rajinder,Taneja, Subhash C.
supporting information, p. 1615 - 1623 (2013/02/22)
The synthesis of both enantiomers of 1,4-benzodioxan-2-carboxylic acid 1, a key synthetic intermediate for the therapeutic agents piperoxan, prosympal, dibozane, and doxazosin was achieved with good yields and high enantioselectivities via the Arthrobacter sp. lipase catalyzed kinetic resolution of ester (±)-17a. The influence of the co-solvents and the immobilization of the lipase upon kinetic resolution demonstrated that immobilized whole cells, in the presence of n-butanol as a co-solvent, resulted in the optimal resolution of the substrate (ee ～99%, E = 535) at 258 mmol (50 g/L) substrate concentration.
Synthesis and biological activity of novel carbacyclins having bicyclic substituents on the ω-chain
Tomiyama,Wakabayashi,Yokota
, p. 1988 - 1996 (2007/10/02)
A number of carbacyclins having bicyclic substituents on the ω-chain have been synthesized and tested for antiplatelet aggregation activity in vitro (against collagen-induced aggregation of rat platelet), for reduction of systemic blood pressure in vivo (ability to reduce the blood pressure in anesthetized rat by iv injection), and for cytoprotective activity (protection against ethanol-induced rat gastric lesion). The most effective compound for each activity was [3aS-[2E,3aα,4α(3R),5β,6aα]]-5-[hexahydro-5-hydroxy-4-[3-hydroxy-3-(2- indanyl)-1-propynyl]-2(1H)-pentalenylidene]pentanoic acid (compound 11a), while some 1,4-benzodioxan analogues had selectivity for organ-protective activity, and indan analogues showed selectivity in their antiaggregation activity.
