synthesis and antifungal evaluation of benzothiazol-2-ylcarbamodithioates

84 Pages·2014·22.02 MB·English

SYNTHESIS AND ANTIFUNGAL EVALUATION OF
BENZOTHIAZOL-2-YLCARBAMODITHIOATES

Thesis

Submitted to the Punjab Agricultural University
in partial fulfillment of the requirements
for the degree of

MASTER OF SCIENCE
in
CHEMISTRY
(Minor Subject: Biochemistry)

By

PRIYA
(L-2012-BS-239-M)

Department of Chemistry
College of Basic Sciences and Humanities
©PUNJAB AGRICULTURAL UNIVERSITY
LUDHIANA – 141 004

2014
1
CERTIFICATE I

This is to certify that the thesis entitled synthesis and antifungal evaluation of

benzothiazol-2-ylcarbamodithioates submitted for the degree of M.Sc., in the subject of
Chemistry (Minor subject: Biochemistry) of the Punjab Agricultural University, Ludhiana, is a
bonafide research work carried out by Priya (L-2012-BS-239-M) under my supervision and

that no part of this thesis has been submitted for any other degree.
The assistance and help received during the course of investigation have been fully
acknowledged.

_______________________
Major Advisor
Dr. (Mrs.) Anjali
Assistant Professor
Department of Chemistry
Punjab Agricultural University
Ludhiana -141004

2
CERTIFICATE II

This is to certify that the thesis entitled synthesis and antifungal evaluation of

benzothiazol-2-ylcarbamodithioates submitted by Priya (Admn. No. L-2012-BS-239-M) to
the Punjab Agricultural University, Ludhiana, in partial fulfillment of the requirements for the
degree of M.Sc. in the subject of Chemistry (Minor subject: Biochemistry) has been approved
by the Student’s Advisory Committee along with Head of the Department after an oral
examination on the same.

________________________ ________________________
{Dr. (Mrs.) K. K. Chahal} (Prof. Ashok Kumar Malik)
Head of the Department External Examiner
Department of Chemistry
Punjabi University, Patiala

________________________
{Dr. (Mrs.) Anjali}
Major Advisor

________________________
(Dr. Gursharan Singh)
Dean Postgraduate Studies

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AAAACCCCKKKKNNNNOOOOWWWWLLLLEEEEDDDDGGGGEEEEMMMMEEEENNNNTTTTSSSS

It gives me immense pleasure to express my thanks and sense of profound gratitude to my
Major Advisor DDDDrrrr.... ((((MMMMrrrrssss....)))) AAAAnnnnjjjjaaaalllliiii, Assistant Professor, Department of Chemistry, Punjab
Agricultural University, Ludhiana, for her expert guidance, encouragement, inspiration and advice
throughout my research work. It was my privilege to be guided by a person of calibre, whose
blessings bring best in every one of my endeavours.
I owe my unpayable debt to the other esteemed members of my advisory committee. DDDDrrrr....
((((MMMMrrrrssss....)))) KKKK....KKKK CCCChhhhaaaahhhhaaaallll, Professor-cum-Head, Department of Chemistry, DDDDrrrr.... ((((MMMMrrrrssss....)))) AAAAnnnniiiittttaaaa GGGGaaaarrrrgggg
Chemist, Department of Chemistry, DDDDrrrr.... VVVViiiinnnneeeeeeeetttt KKKKuuuummmmaaaarrrr, Professor, Department of Plant Pathology,
and DDDDrrrr.... ((((MMMMrrrrssss....)))) SSSSaaaattttvvvviiiirrrr KKKKaaaauuuurrrr Assistant Biochemist, Department of Biochemistry for their able
guidance , constructive suggestions and continuous support.
I am indebted to my respected ppppaaaarrrreeeennnnttttssss for their heartful blessings and deep affection that
enabled me to this stage of career. I want to thank my uncle ((((MMMMrrrr....)))) SSSSaaaannnnjjjjeeeeeeeevvvv SSSShhhhaaaarrrrmmmmaaaa for his constant
words of encouragement and support. I am also thankful to SSSSaaaammmmeeeeeeeerrrr, my younger brother for helping
me whenever needed.
Friends are always a moral support which is extremely important when one is feeling low. I
give my special thanks to my best friends NNNNaaaavvvvnnnneeeeeeeetttt aaaannnndddd PPPPaaaaaaaawwwwaaaannnn,,,, for supporting me when times were
stressful. I wholeheartedly thank my senior and junior, KKKKhhhhuuuusssshhhhbbbbuuuu and SSSShhhhaaaarrrruuuu for their help as and
when required.... I also thank ((((MMMMrrrrssss....)))) BBBBhhhhiiiinnnnddddeeeerrrr kkkkaaaauuuurrrr, lab attendant for every possible help.
I feel proud to be a part of PAU, Ludhiana where I learnt a lot and spent some
unforgettable moments of my life.
Last but not least, I thank my GGGGoooodddd for everything.

________________________________________
PPPPrrrriiiiyyyyaaaa

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Title of the Thesis : Synthesis and antifungal evaluation of benzothiazol-
2-ylcarbamodithioates.

Name of the Student : Priya
Admission No. L-2012-BS-239-M

Major Subject : Chemistry
Minor Subject : Biochemistry
Name and Designation : Dr. (Mrs.) Anjali
of Major Advisor Assistant Professor
Degree to be Awarded : M.Sc.
Year of Award of Degree : 2014
Total Pages in Thesis : 76
Name of University : Punjab Agricultural University
Ludhiana -141004

ABSTRACT

A series of novel carbamodithioates with benzothiazole scaffold have been synthesized
and characterized on the basis of Infrared (IR) and Proton Nuclear Magnetic Resonance
(1H NMR) and Mass Spectrometry. The synthesized compounds were evaluated for their
antifungal activity against various phytopathogenic fungi viz. Pyricularia grisea, Drechslera
oryzae, Colletotrichum falcatum and Ustilago hordei by spore germination inhibition method
and results were expressed in terms of ED values. All the compounds showed mild to
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moderate results against the test fungi. Compounds 1, 4a and 1b were found to be most active
against U. hordei with ED values 140, 150 and 140 µg/ml respectively. Benzo[d]thiazol-2-
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amines have been found to be more active than their carbamodithioate analogues. Chemical
lead hybridisation of two bioactive scaffolds had neutral effect on the fungitoxicity against all
the test fungi.

Key words: Benzo[d]thiazol-2-amine, Potassium (benzo[d]thiazol-2-yl)carbamodithioates,
butyl/ethyl (benzo[d]thiazol-2-yl)carbamodithioates and antifungal potential.

_________________________ _________________________
Signature of Major Advisor Signature of the Student

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CONTENTS

Chapter Topic
Page
I. INTRODUCTION 1-3
II. REVIEW OF LITERATURE 4-25
III. MATERIALS AND METHODS 26-33
IV. RESULTS AND DISCUSSION 34-64
V. SUMMARY 65-66
REFERENCES 67-76
VITA

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CHAPTER I
INTRODUCTION

Carbamodithioates belong to aza-thio category of compounds, represented by a general
formula (R R )N-(C=S)-SX, where R , R includes alkyl, alkylene, aryl, or similar other group,
1 2 1 2
and X is usually metal ion or alkyl. These are actually the subclass of carbamates in which both
oxygen atoms are replaced by sulfur atoms.

Organic carbamodithioates have attracted a great deal of importance due to their
interesting chemistry and wide utility (Han and Porco 2007, Rafin et al 2000, Greene and Wuts
1999, Chaturvedi and Ray 2006, Crich and Quintero 1989). They are valuable synthetic
intermediates (Boas et al 2004) which are ubiquitously found in a variety of biologically active
compounds and exhibit valuable biological effects (Mamba et al 2010, Awang et al 2011) that
includes antibacterial activity (Rani and Thirumaran 2013, Husain et al 2011, Shaheen et al
2007), antifungal (Shahnaz et al 2013, Mujawar et al 2014, Qin et al 2012), antitumor (Huang
et al 2009, Zahran et al 2008), anticancer activity (Zhang and Talalay 1994), antimicrobial
(Basirah et al 2013, Palanisamy and Subbiah 2013), antimycobacterial (Guzel and Salman
2006), antiproliferative (Duan et al 2013), antitubercular (Horita et al 2011), antioxidant
activity (Schreck et al 1992), inhibition of cardiac hypertrophy (Ha et al 2005), inhibition of
cell apoptosis (Wolfe et al 1994, Wu et al 2012), inhibition of corrosion (Li et al 2012),
inhibition of hypertension (Yavuz et al 2013) etc. In addition they have number of other
applications such as in photochemistry (Plyusnin et al 1997), catalyst in the vulcanization of
rubber (Nieuwenhuizen 2001), detection and analysis of biological nitric oxide produced
endogenously by the action of nitric oxide synthases (Fujii and Yoshimura 2000) and in
polymerization (Mayadunne et al 1999). They are also part of some natural products which
includes brassinin [methyl ((1H-inden-3yl) methyl)carbamodithioate] (Mehta et al 1995)
isolated from cabbage and Sulforamate [methyl4-(methylsulfinyl)butylcarbamodithioate] with
potential anticancer activity (Gerhauser et al 1997).
The carbamodithioate family plays a pivotal role in agriculture on account of multifaceted
reasons viz. multisite mode of action (Charles 1980), low mammalian toxicity, high efficiency
in controlling various plant pathogenic fungi (Pease and Holt 1977, Qin et al 2012) and little
resistance developed towards carbamodithioates (Chauhan et al 2012). They are known for
commercial applications since 1930’s (Ware and Whitacre 2004) and are a part of a large group
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of synthetic organic compounds that have been developed worldwide as fungicides. They are
used for treatment of seeds, soil, foliar and postharvest diseases affecting several types of crops
(Rafin et al 2000). Uptil now there are more than 15 carbamodithioates with commercial
applications as fungicides are available. Among them thiram, disulfiram, ziram, and ferbam are
some common fungicides used commercially.
Benzothiazole (2) is another nitrogen-sulfur heterocyclic moiety which possess broad
spectrum of biological activities like antibacterial (Srivastava and Sen 2008), anti-inflammatory
(Karbasanagouda et al 2008), antifungal (Pattan et al 2009), antitubercular (Shanta and Bharti
2001), antitumor (Nadeem et al 2009), antioxidant (Geronikaki et al 2003) etc. It is a versatile
motif because of biocidal unit (S‐C=N) which is easily metabolised inside the body and is
already been a parent structure in many synthetic drugs, that have been used for the treatment
of infective diseases (Hargrave et al 1983, Tsuji and Ishikawa 1994). This appeared frequently
in the structure of various natural products and biologically active compounds like thiamine
(vitamin-B), in some antibiotics like penicillin, micrococcin, and metabolic products of fungi
and primitive marine animal. It is also a precursor for synthesis of many compounds including
sulfur drugs, biocides, fungicides etc. It is present in range of commercially available antifungal
compounds for agriculture use (Cajka et al 2011). Most common benzothiazole fungicides
include TCMTB [2-(thiocyanomethylthio)benzothiazole], an effective soil fungicide used as
seed dresser with LD 1590 mg/kg (Wang et al 2005), 2-mercaptobenzothiazoles that possess
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broad spectrum bioactivity profile (Mohammed and Bhojraj 2012), tricyclazol [1,2,4-
Triazolo[3,4-b]benzothiazole, 5-methyl], which is effective against rice blast disease
(P.oryzae).The structure-activity relationship of 2-aminobenzothiazole (X = NH ) interestingly
2
revealed that change of the substituent group at C-2 position commonly results in the change of
its bioactivity (Fenglian et al 2007).

Thousands of carbamodithioate have been developed and vast majority of them
contains only simple alkyl substituents on S side (Dhooghe and Kimpe 2006). So,
functionalization of the backbone is a developing area in carbamodithioate chemistry
(Nabipour et al 2010). Scanty work is reported on the synthesis and use of benzo thiazol-2-
ylcarbamodithioates as agrochemicals. Bringing two bioactive centres in a single molecule may
result in enhancement of biological potential of the molecules (Kokil et al 2010, Mandeep et al
2013, Sidhu et al 2010). The present work was aimed at chemical hybridization of two
bioactive leads i.e. benzothiazol-2-yl with carbamodithioate in a single molecule, and their
antifungal evaluation against various phytopathogenic fungi. So the present research has been
2
designed with following objectives:
1. To synthesize benzothiazol-2-amines.
2. To synthesize benzothiazol-2-ylcarbamodithioates from above synthesized
benzothiazol-2-amines.
3. To evaluate antifungal potential of synthesized benzothiazol-2-ylcarbamodithioates
against various phytopathogenic fungi.
The thesis runs into several chapters, namely, review of literature, materials and
methods, results and discussion and summary.
Since almost the entire investigation incorporated in the thesis is on synthesis of
benzothiazol-2-amines and benzothiazol-2-ylcarbamodithioates and their antifungal activity,
thus the review given in chapter II was considered to be appropriate. Chapter III includes the
various techniques and methods employed for the synthesis and antifungal evaluation of
compounds. Chapter IV is devoted to results and discussion. Chapter V gives summary of
research work carried out. The references cited in the text are alphabetically arranged at the end
of the thesis.

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