Extensions of the Leuckart Synthesis of Amines

A series of 2-cyano-3-methylthio-3-substituted methylaminoacrylates were synthesized as herbicidal inhibitors of photosystem II (PSII) electron transport, in order to estimate the effect of fluorine atom, pyridyl group, chirality and ester chain on activity. The important intermediate 2-fluoro-5-aminomethylpyridine was synthesized with high yield. The bioassay results showed that most of title compounds had high herbicidal activity in postemergence treatment. The introduction of an α-methyl into the 3-substituted methylamino could improve the activity notably. The replacement of hydrogen by chlorine or fluorine group and phenyl by pyridyl group showed different effects, and at the same time, the ester chain affected the activity too.

show abstract

“…Racemic (±)-α-(p-chlorophenyl)ethylamine was prepared from p-chloroacetophenone by the Leuckart reaction. 15 …”

Section: Methodsmentioning

confidence: 99%

Synthesis and Herbicidal Activity of 2‐Cyano‐3‐methylthio‐3‐substituted Methylaminoacrylates

Gao

Zou

et al. 2006

Chin. J. Chem.

View full text Add to dashboard Cite

show abstract

“…(4.112) [182], in which MW-specific effects were apparent at 80 • C but were masked at 110 • C. A striking example in which all these conditions are fulfilled may be the Leuckart reductive amination of carbonyl compounds. This reaction is well known but, unfortunately, using classical procedures is only possible under very harsh conditions (temperature 240 • C, sealed containers, and extended reaction times) and gives modest yields (≤ 30%) [219]. These difficulties are a good challenge to check the effectiveness of MW irradiation because the mechanism develops a dipolar TS (Scheme 4.26, Table 4.32) [220], and this should also favor involvement of a MW 210 12 This is a distinctive example of a pronounced MW effect for a reaction occurring with a very late dipolar TS.…”

Section: Conclusion: Suitable Conditions For Observation Of Specific mentioning

confidence: 99%

Nonthermal Effects of Microwaves in Organic Synthesis

Perreux¹,

Loupy²,

Petit³

2012

Microwaves in Organic Synthesis

View full text Add to dashboard Cite

“…4-Phet1oxypropiopl1e11ot1e was prepared in 82% yield by reacting diphenyl ether and propionic anhydride under Friedel-Crafts conditions according to the method of Ingersoll et al (19), bp 135-14O0C/0.06 torr; nrnr 6 1.2 (t, 3H), 2.8 (q, 2H), 6.8-9.0 (m, 9H).…”

Section: 4-di11itrobet1ze11es11~e11yl Chloride Was Prepared By the mentioning

confidence: 99%

“…Retention time on a 20 f t X 3 in. 30% 35-30 column at 140 "C, with a flow rate of 45 ml per min is 27 min; nmr 6 4-Isopropoxypropiopher~one was prepared by the FriedelCrafts acylation of phenyl isopropyl ether according to the procedure of lngersoll et al (19). The phenyl isopropyl ether was made according to the procedure of Olsen et al (21).…”

Section: 4-di11itrobet1ze11es11~e11yl Chloride Was Prepared By the mentioning

confidence: 99%

The addition of 2,4-dinitrobenzenesulfenyl chloride to a series of phenyl substituted cis- and trans-1-phenylpropenes

Sçhmid¹,

Nowlan²

1976

Can. J. Chem.

View full text Add to dashboard Cite

ethane 25 "C, on a mesurC la vitesse d'addition du chlorure de dinitro-2,4 benzenesulfknyle B des phCnyl-1 prop'enes cis et tratls substituCs sur le noyau aromatique par des nitro-3, chloro-4, mCthyl-4, mCthoxy-4, phknoxy-4 et isopropoxy-4; on a aussi dCterminC la stCrCochimie des produits. Alors que l'on obtient une relation linbire entre log k2 vs. soit u ou U+ on obtient une meilleure correlation avec U . On obtient une telle relation linhire m&me si la stCrCochimie des produits change de stCreospkifique et nonrkgiospkifique pour les substituants Clectro-attracteurs (nitro-3 et chloro-4) h regiospkifique et non stCrCospCcifique pour les substituants Clectro-donneurs (mkthoxy-4, phCnoxy-4 et isopropoxy-4). Les rksultats suggkrent que 1'Ctape dkterminante, pour toutes ces additions, est un ion ponte et que tous les ions ouverts se forrnent aprks cette Ctape.[ The rate of addition of 2,4-dinitrobenzenesulfenyl chloride to cis and t~atls 3-NO2, 4-CI, 4-CH3, 4-OCH3, 4-OCsHs, 4-0CH(CH3)2 substituted-1-phenylpropenes has been measured in 1,1,2,2-tetrachloroethane at 25 "C and the product stereochemistry has also been determined. While a plot of log k2 vs. either u or U+ is linear a better correlation is obtained with U . Such a linear relationship is obtained even though the product stereochemistry changes from stereospecific and nonregiospecific for electron-withdrawing substituents (3-N02, 4-CI) to regiospecific and nonstereospecific for electron-donating substituents (4-OCH3, 4-OCsHs, and 4-0CH(CH3)2). These results suggest that the rate determining step for all the additions is bridged and that any open ion is formed after this step.The recent report of the addition of 2,4-dinitrobenzenesulfenyl chloride to cis-and transanethole is the first example of a nonstereospecific addition of an arenesulfenyl chloride to an alkene (2). In this reaction an open carboniuin ion is clearly involved as an intermediate prior to the product determining step. However it is not clear if the first formed intermediate is also an open carbonium ion. In an attempt to obtain more information about the mechanism of this reaction we have examined the rate of addition of 2,4-dinitrobenzenesulfenyl chloride to a series of phenyl substituted cis-and trans-l-phenylpropenes (la-g and 20-g).The purpose of this study is to determine if there is a break in the Harnmett crp plot at the point where the addition becomes nonstereospecific. In this way, we should be able to determine if there is a change in the structure of the rate determining transition state as the product stereochemistry changes. ResultsThe rates of addition of 2,4-dinitrobenzenesulfenyl chloride to a series of phenyl substituted cis-(la-g)-and trans-(2a-g)-1-phenylpropenes were measured at 25 "C in 1,1,2,2-tetrachloroethane (TCE) by two methods: a titrimetric method and a dilatometry method using an Anton Paar precision density meter. The additions were found to exhibit normal second-order kinetics, first-order in alkene and first-order in sulfenyl chloride to 80% completion o...

show abstract

Extensions of the Leuckart Synthesis of Amines

Cited by 65 publications

References 0 publications

Synthesis and Herbicidal Activity of 2‐Cyano‐3‐methylthio‐3‐substituted Methylaminoacrylates

Synthesis and Herbicidal Activity of 2‐Cyano‐3‐methylthio‐3‐substituted Methylaminoacrylates

Nonthermal Effects of Microwaves in Organic Synthesis

The addition of 2,4-dinitrobenzenesulfenyl chloride to a series of phenyl substituted cis- and trans-1-phenylpropenes

Contact Info

Product

Resources

About