139. The associating effect of the hydrogen atom. Part VIII. The N–H–N bond. Benziminazoles, glyoxalines, amidines, and guanidines

Hunter, Louis; Marriott, J. A. R.

doi:10.1039/jr9410000777

Cited by 33 publications

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“…Hunter and Marriott, on determining the molecular weights of substituted amidines (V) and imidazoles (VI) (which can be regarded as cyclic amidines) in naphthalene over a range of concentration, concluded that members of these two classes have pronounced tendencies toward self-association by NH...N formation [184]. In accord with their expectations, compounds without an NH group (as, for example, 1,2-dimethylbenzimidazole) are not associated.…”

Section: Aliphatic Aminesmentioning

confidence: 89%

Acid-base behavior in aprotic organic solvents

Davis¹

1968

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Butyl hydroperoxide and deuteroperoxide. Deuterium isotope effects on hydrogen bonding by Br0nsted acids 40 4.3. Hydrogen-bonded ion pairs 41 4.3.1. Conductance 41 a. Walden's work 42 b. Wynne-Jones' postulate 42 c. Investigations of Kraus, Fuoss, and associates... 43 d. Summary 45 4.3.2. Dielectric constants 46 a. Dielectric polarization of substituted ammonium picrates and halides in benzene 46 b. Dielectric polarization of other acid-base complexes in benzene 47 4.3.3. CoUigative properties 49 a. Cryoscopy 50 Page b. The differential vapor pressure (DVP) method... 51 104 4.5.6. Homoconjugation of other organic and inorganic acids a. Perchloric acid 105 b. Other acids 105 4.5.7. Heteroconjugate anions 105 a. Chemical behavior 105 b. Physical measurements 108 4.6. Concluding discussion of hydrogen bonding 112 4.6.1. Definition of a hydrogen bond. Systems which form hydrogen bonds 112 4.6.2! Some recent concepts of hydrogen bonding 113 5. Acidity and basicity scales in aprotic organic solvents... 114 5.1. Early attempts to determine relative acidities 114 5.2. Log Kbha scales of acidity and basicity 115 5.3. Methods used in determining values of log A^bha 116 5.4. Tables of log ^bha, and AS obtained using aprotic solvents 118 5.4.1. Aromatic and substituted aromatic hydrocarbons 118 a. Benzene 118 b. Anisole and chlorobenzene 126 5.4.3. Carbon tetrachloride 126 5.4.4. Chloroform 128 5.4.5. Miscellaneous aprotic solvents 129 6. Acid-base titrations in completely aprotic solvents 133 6.1. Introduction 133 6.2. Titrations with indicator dyes in completely aprotic solvents 133 6.3. Instrumental procedures for detecting end-points in completely aprotic solvents 133 6.3.1. Conductance titrations 133 iv Contents -Continued Page 6.3.2. Dielectrometric titrations 133 6.3.3. Photometric titrations 134 6.3.4. Thermometric titrations 135 6.3.5. Titrations by the DVP method 135 6.3.6. Cryoscopic titrations 135 6.3.7. Other possible instrumental procedures 135 a. Refractive index 135 b. Density 135 c. Optical rotation 135 6.4. Reference acids and bases for aprotic organic solvents 135 6.4.1. Acids 135 a. Hydrogen chloride 135

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Section: Aliphatic Aminesmentioning

confidence: 89%

Acid-base behavior in aprotic organic solvents

Davis¹

1968

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“…28 These curves correspond to the followin g mixtures in benzene as solvent: (1) The relationship postulated in eq 2, if valid, should give linear curves, with unit n egative slope. Th!l lines were drawn so as to give greatest weight to the values that can b e meas ured with the grea test precision, that is, those for which the ratio [68], from measurements of molecular weights in naphthalene, concluded th at 1,3-diphenylguanidine and related compounds are partly associated in this solvent. However, th e solutions used in th e experiments described in this paper were so dilute that the degree of association of th e b ase should be very small.…”

Section: Acid·base Reactions In Organic Solventsmentioning

confidence: 99%

Acid-base reactions in benzene and other organic solvents: Behavior of bromphthalein magenta with different classes of organic bases

Davis¹,

Schuhmann²

1947

J. RES. NATL. BUR. STAN.

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Practical and theoretica l aspects of acid-base reactions in benzene and other organic solvents al'e discussed . The synthesis of the indicators bromphtha lein magenta E and B (the ethyl and n-butyl esters of t etrabromopheno lph thale in ) an d of their t etraalkylammonium salts is descri bed. Qualitative and spectrophotometric data concern in g the color reactions of the indicators with primary, seconda ry, and t ertia ry a li phatic amines , s ubstituted guan idines, a nd other n itrogen bases in benz ene and other types of organic solvents are presen ted. An expla nati on off ered for the color phenom ena is also appli cable to ulfon ephthalcins and other indicators.Examples are given of the qu antitative m eas urement of the relative reactivity of bases with bromphthal ein magenta in benzene. Illust rations a re furnishe d of the app li cation of the ind icato rs to the quantitative estimation of acids and bases, to measu rem ents of the relative s trengt,h s of orga ni c acids, and to the differen tiation o f primary, secondary, and tertiary a liphatic a mines.During t he sp ectrophotometric inves t igations, it was necessar y to des ign new types of a bsorption cells s uitable fo r vo latile solvents a nd for th in laye rs of solu t ion. A desc ription of the e cells is given.

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“…Carbendazim was treated with methyl chloroformate to give methyl I-(methoxycarbonyl)benzimidazol-2-ylcarbamate. The (16) by Pfizer Inc. The purity of the compounds was established by thin-layer chromatography and the structures confirmed by infrared and mass spectra.…”

Section: Experimental 21 Materialsmentioning

confidence: 99%

The antifungal activity of alkyl benzimidazol‐2‐ylcarbamates and related compounds

Eckert

Rahm

1979

Pestic. Sci.

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The fungistatic activity against Penicillium digitatum and Diplodia natalensis decreased slightly in ascending a homologous series of alkyl esters of benzimidazol‐2‐ylcarbamic acid from the methyl ester (carbendazim) to the pentyl ester; the hexyl and octyl esters were inactive. 2‐(Acylamino)benzimidazoles were slightly less active than the analogous alkyl benzimidazol‐2‐ylcarbamates. Introduction of a methylene bridge between the benzimidazole ring and the 2‐methoxycarbonylamino group abolished antifungal activity. Methylation of either the carbamate nitrogen or an imidazole nitrogen of carbendazim produced inactive compounds. Replacement of the benzimidazole ring of carbendazim with various other ring systems was accompanied by marked reduction in antifungal activity.

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139. The associating effect of the hydrogen atom. Part VIII. The N–H–N bond. Benziminazoles, glyoxalines, amidines, and guanidines

Cited by 33 publications

References 0 publications

Acid-base behavior in aprotic organic solvents

Acid-base behavior in aprotic organic solvents

Acid-base reactions in benzene and other organic solvents: Behavior of bromphthalein magenta with different classes of organic bases

The antifungal activity of alkyl benzimidazol‐2‐ylcarbamates and related compounds

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