Practical Synthesis of 1,2,3,4-Tetrahydroisoquinoline-1-phosphonic and -1-phosphinic Acids through Kabachnik–Fields and Aza-Pudovik Reaction

Synthesis ◽  
2019 ◽  
Vol 52 (05) ◽  
pp. 769-774
Author(s):  
Jesús Tadeo Hernández-Moreno ◽  
Ivan Romero-Estudillo ◽  
Carlos Cativiela ◽  
Mario Ordóñez

We report here an alternative and practical method for the preparation of 1,2,3,4-tetrahydroisoquinoline-1-phosphonic acid and the first synthesis of 1,2,3,4-tetrahydroisoquinoline-1-H-phosphinic and 1,2,3,4-tetrahydroisoquinoline-1-phenylphosphinic acids through Kabachnik–Fields and aza-Pudovik reaction. This methodology does not require any metallic catalyst and proceeds under mild reaction conditions.

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1897
Author(s):  
Hideyasu China ◽  
Nami Kageyama ◽  
Hotaka Yatabe ◽  
Naoko Takenaga ◽  
Toshifumi Dohi

We report a convenient and practical method for the preparation of nonexplosive cyclic hypervalent iodine(III) oxidants as efficient organocatalysts and reagents for various reactions using Oxone® in aqueous solution under mild conditions at room temperature. The thus obtained 2-iodosobenzoic acids (IBAs) could be used as precursors of other cyclic organoiodine(III) derivatives by the solvolytic derivatization of the hydroxy group under mild conditions of 80 °C or lower temperature. These sequential procedures are highly reliable to selectively afford cyclic hypervalent iodine compounds in excellent yields without contamination by hazardous pentavalent iodine(III) compound.


Organics ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 107-117
Author(s):  
Mattia Forchetta ◽  
Valeria Conte ◽  
Giulia Fiorani ◽  
Pierluca Galloni ◽  
Federica Sabuzi

Owing to the attractiveness of organic phosphonic acids and esters in the pharmacological field and in the functionalization of conductive metal-oxides, the research of effective synthetic protocols is pivotal. Among the others, ω-bromoalkylphosphonates are gaining particular attention because they are useful building blocks for the tailored functionalization of complex organic molecules. Hence, in this work, the optimization of Michaelis–Arbuzov reaction conditions for ω-bromoalkylphosphonates has been performed, to improve process sustainability while maintaining good yields. Synthesized ω-bromoalkylphosphonates have been successfully adopted for the synthesis of new KuQuinone phosphonate esters and, by hydrolysis, phosphonic acid KuQuinone derivatives have been obtained for the first time. Considering the high affinity with metal-oxides, KuQuinones bearing phosphonic acid terminal groups are promising candidates for biomedical and photo(electro)chemical applications.


Synlett ◽  
2020 ◽  
Author(s):  
Jin Jiang ◽  
Lili Xiao ◽  
Yu-Long Li

AbstractBecause molecular iodine and hydrosilanes are stable to both air and moisture, reactions using these reagents are easy to operate and require mild reaction conditions. Molecular iodine and a hydrosilane were used to reduce N-sulfonyl aldimines to the corresponding N-alkylsulfonamides. This transformation is a practical method for the synthesis of N-alkylsulfonamides.


Synthesis ◽  
2019 ◽  
Vol 51 (07) ◽  
pp. 1643-1648 ◽  
Author(s):  
David Knight ◽  
Thomas Wirth ◽  
Abdul Hadi Aldmairi

Substituted morpholin-2-one derivatives were readily obtained in two steps starting from commercially available N-protected amino acids. In a metal-free and practical method, a catalytic amount of trifluoromethanesulfonic acid was sufficient to generate morpholinones under mild reaction conditions in an intramolecular hydroamination reaction in good to excellent yields.


Synthesis ◽  
2019 ◽  
Vol 51 (07) ◽  
pp. 1561-1564 ◽  
Author(s):  
Kentaro Okano ◽  
Ryo Nakura ◽  
Kazuki Inoue ◽  
Atsunori Mori

This study investigated a practical method for regiocontrolled synthesis of precursors of strained cyclohexynes and 1,2-cyclohexadienes, which is a one-pot procedure consisting of a rearrangement of silyl enol ether and subsequent formation of the enol triflates. Triethylsilyl enol ether, derived from cyclohexanone, was treated with a combination of LDA and t-BuOK in n-hexane/THF to encourage the migration of the silyl group to generate an α-silyl enolate. Subsequently, the α-silyl enolate was reacted with Comins’ reagent to yield the corresponding enol triflate. Finally, the α-silylated trisubstituted lithium enolate for the synthesis of 1,2-cyclohexadiene precursor was isomerized in the presence of a stoichiometric amount of water for one hour at room temperature to exclusively provide tetrasubstituted lithium enolate for the synthesis of cyclohexyne precursor in one pot.


2013 ◽  
Vol 830 ◽  
pp. 151-154 ◽  
Author(s):  
Yue Hai You ◽  
Shan Shan Gong ◽  
Qi Sun

Derivatives of 3β-amino-5-cholestene are of substantial interest to chemical biologists and have potential medicinal value. A novel and practical method for the preparation of 3β-amino-5-cholestene from inexpensive cholesterol has been developed. To synthesize the epicholesterol intermediate, the KO2 method reported by Corey and coworkers was applied in this synthetic route and solved the problems of the known synthetic route involving epicholesterol intermediate.


1989 ◽  
Vol 42 (2) ◽  
pp. 301 ◽  
Author(s):  
HG Mcfadden ◽  
RLN Harris ◽  
CLD Jenkins

Analogues of phosphoenolpyruvate (PEP), the substrate of PEP carboxylase , were synthesized as potential inhibitors of the enzyme. Esterified analogue precursors were obtained by nucleophilic substitution of various halomethacrylate derivatives with trialkyl phosphites. Substitution of the halomethacrylates can occur either α to the leaving halogen or in the γ position with subsequent allylic shift of the double bond. The course of the reaction was influenced both by reaction conditions and the nature of the substituents on the reactants. The phosphonomethacrylates obtained were hydrolysed to PEP analogues that were found to be moderate to good inhibitors of PEP carboxylase. Phosphonomethacrylic acid derivatives bearing two halogen substituents in the γ position were found to be the most potent inhibitors of this enzyme.


Synlett ◽  
2018 ◽  
Vol 29 (07) ◽  
pp. 959-963
Author(s):  
Jian-Jun Li ◽  
Zhiwei Chen ◽  
Yangyang Fan ◽  
Lei Zheng ◽  
Zhaohai Yang

This work discloses a novel and efficient protocol for the construction of functionalized chromeno[3,4-c]pyridine derivatives from the Blaise reaction intermediates and 3-cyanocoumarins through a CuCl2-catalyzed sequential Michael addition/intramolecular cyclization/oxidative aromatization reaction. This new method shows the advantages of mild reaction conditions, easy workup, nonchromatographic purification technique, good functional group tolerance, and moderate to good yields.


2019 ◽  
Vol 6 (13) ◽  
pp. 2220-2225 ◽  
Author(s):  
Xu Qiu ◽  
Xiaoxue Yang ◽  
Yiqun Zhang ◽  
Song Song ◽  
Ning Jiao

A novel M2CO3-catalyzed aerobic oxidative heterocoupling of thiols with air as the oxidant was described for the synthesis of unsymmetrical disulfides. High atom economy, green catalyst and oxidant, mild reaction conditions, and broad substrate scope make this strategy extremely attractive.


2020 ◽  
Vol 16 ◽  
pp. 798-808
Author(s):  
Dong Cai ◽  
ZhiHua Zhang ◽  
Yufan Meng ◽  
KaiLi Zhu ◽  
LiYi Chen ◽  
...  

In the present study, a practical method to prepare piperazinyl amides of 18β-glycyrrhetinic acid was developed. Two main procedures for the construction of important intermediate 8 are discussed. One procedure involves the amidation of 1-Boc-piperazine with 3-acetyl-18β-glycyrrhetinic acid, prepared by the reaction of 18β-glycyrrhetinic acid with acetic anhydride without any solvent at 130 °C. The other procedure to prepare compound 8 involves the amidation of 18β-glycyrrhetinic acid followed by the esterification with acetic anhydride. Finally, compound 8 underwent N-Boc deprotection to prepare product 4. To ascertain the scope of the reaction, another C-3 ester derivative 17 was tested under the optimized reaction conditions. Furthermore, the reasons for the appearance of byproducts were elucidated. Crystallographic data of a selected piperazinyl amide is reported.


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