3-substituted anilines as scaffolds for the construction of glutamine synthetase and DXP-reductoisomerase inhibitors

Article abstract of DOI:10.1080/00397910802663444

Access to a series of truncated ATP analogs, as potential anti-tuberculosis agents, has been explored via alkylation and acylation of 3-aminophenol, whereas chloroacetylation, using chloroacetyl chloride, and subsequent Arbuzov phosphonation of a series of 3-substituted anilines have afforded a series of phosphonate derivatives as potential antimalarial agents.

Full text of DOI:10.1080/00397910802663444

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3-Substituted Anilines as
Scaffolds for the Construction
of Glutamine Synthetase
and DXP-Reductoisomerase
Inhibitors
Marius Mutorwa a , Sheriff Salisu a , Gregory L.
Blatch b c , Colin Kenyon d & Perry T. Kaye a c
a Department of Chemistry , Rhodes University ,
Grahamstown, South Africa
b Department of Biochemistry, Microbiology, and
Biotechnology, Rhodes University , Grahamstown,
South Africa
c Centre for Chemico- and Biomedicinal Research ,
Rhodes University , Grahamstown, South Africa
d CSIR BIO/CHEMTEK, Modderfontein , South Africa
Published online: 26 Jun 2009.
To cite this article: Marius Mutorwa , Sheriff Salisu , Gregory L. Blatch , Colin Kenyon
& Perry T. Kaye (2009) 3-Substituted Anilines as Scaffolds for the Construction
of Glutamine Synthetase and DXP-Reductoisomerase Inhibitors, Synthetic
Communications: An International Journal for Rapid Communication of Synthetic
Organic Chemistry, 39:15, 2723-2736, DOI: 10.1080/00397910802663444
To link to this article: http://dx.doi.org/10.1080/00397910802663444

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Synthetic Communications1, 39: 2723–2736, 2009
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print=1532-2432 online
DOI: 10.1080/00397910802663444
3-Substituted Anilines as Scaffolds
for the Construction of Glutamine Synthetase
and DXP-Reductoisomerase Inhibitors
Marius Mutorwa,1 Sheriff Salisu,1 Gregory L. Blatch,2,3
Colin Kenyon,4 and Perry T. Kaye1,3
1Department of Chemistry, Rhodes University, Grahamstown,
South Africa
2Department of Biochemistry, Microbiology, and Biotechnology,
Rhodes University, Grahamstown, South Africa
3Centre for Chemico- and Biomedicinal Research, Rhodes University,
Grahamstown, South Africa
4CSIR BIO=CHEMTEK, Modderfontein, South Africa
Abstract: Access to a series of truncated ATP analogs, as potential anti-
tuberculosis agents, has been explored via alkylation and acylation of 3-amino-
phenol, whereas chloroacetylation, using chloroacetyl chloride, and subsequent
Arbuzov phosphonation of a series of 3-substituted anilines have afforded a series
of phosphonate derivatives as potential antimalarial agents.
Keywords: Aniline derivatives, DXP-reductoisomerase inhibitors, glutamine
synthetase, phosphonates
Malaria and tuberculosis (TB) constitute enormous health threats in the
developing world. Treatment is compounded by the phenomenon of drug
resistance, and the development of novel therapeutics has become a
research priority. Mycobacterium tuberculosis (Mtb), the organism
responsible for TB,[1] has been shown to release extracellular proteins
that are vital for its replication and virulence in the host’s tissues.[2–5]
Received October 27, 2008.
Address correspondence to Perry T. Kaye, Department of Chemistry, Rhodes
University, Grahamstown, 6140, South Africa. E-mail: P.Kaye@ru.ac.za
2723

2724
M. Mutorwa et al.
Among these proteins is the enzyme, glutamine synthetase (Mtb-GS),
that is essential for the formation of the cell wall of Mtb.[6] The
differences between human and bacterial GS (and in their respective
modes of regulation[7]) has led to the identification of Mtb-GS as a ther-
apeutic target[4] and to the investigation of adenine triphosphate (ATP)
analogs as potentially selective inhibitors of Mtb-GS.[8]
Plasmodium falciparum (Pf), on the other hand, is the parasite respon-
sible for the most dangerous form of human malaria. The enzyme
1-deoxy-1-D-xylulose-5-phosphate (DXP)–reductoisomerase is involved
in a parasite-specific, isoprenoid biosynthetic pathway, for which fosmido-
mycin[9] and FR900098[10] act as inhibitors. In parallel programs in our
laboratories, attention has been given to designing and synthesising ATP
1 and DXP 2 analogs as potential Mtb-GS and DXP-reductoisomerase
inhibitors, respectively. In this article, we report the preparation of a range
of 3-substituted aniline derivatives as DXP and truncated ATP mimics.
It was envisaged that benzenoid compounds 4 with suitable meta
substituents could serve as truncated mimics (Fig. 1) of the 6-aminopur-
ine (adenine) nucleus 3 and that reaction with various electrophiles (as
outlined in Scheme 1) could provide convenient access to novel and effec-
tive ATP analogs (e.g., compound 5 as illustrated in Fig. 1).
Treatment of 3-aminophenol 6a with NaH and a series of alkylating
and acylating agents afforded the range of substitution products
illustrated in Scheme 1. Given the presence of two nucleophilic functional
groups (phenolic and amino) in the substrate 6a, alkylation and=or acyla-
tion of either was not unexpected. The reaction with allyl bromide, in
fact, afforded three products, viz., the mono-allylated product 7 and
the bis-allylated isomers 8 and 9. Mass spectrometric (MS) analysis
revealed a molecular ion at m=z 149 (as the base peak) for the mono-
allylated product 7, whereas the di-allylated products 8 and 9 each
exhibited a molecular ion at m=z 189 (95% and 100% relative abundance,
respectively). The allylation sites in each of the products were established
by comparison of the experimental chemical shifts of the methylene
13CNMR signals, and the assignments were supported by the correspond-
ing Modgraph-predicted[11] values. Moreover, in the 1H NMR spectra of
N-allyl-3-hydroxyaniline 7, N-allyl-3-allyloxyaniline 8, and N,N-diallyl-3-
-hydroxyaniline 9, the N-methylene protons have similar chemical shift
values (ca. 3.8 ppm), whereas the O-methylene protons in the O-allylated
moiety 8 resonate downfield at 4.51 ppm because of the greater deshield-
ing effect of the oxygen atom (Fig. 2). Unfortunately, attempts to dihy-
droxylate the mono-allylated product 7 using cetyltrimethylammonium
permanganate (CTAP), KMnO4, and NaIO4 all proved unsuccessful.
The mono- and di-acylated products (10 and 11, respectively) were
isolated in very poor yields when the substrate 6a was treated with

3-Substituted Aniline Derivatives
2725
Scheme 1. Alkylation and acylation reactions.
NaH and acryloyl chloride. Remarkably, however, only the correspond-
ing N-mono-acylated products (12, 13, and 14) were isolated from the
acylation reactions involving chloroacetyl chloride, acetoxyacetyl chlor-
ide, and penta-O-acetyl-D-gluconyl chloride.
2-Acetoxy-N-(3-hydroxyphenyl)acetamide 12 exhibited phenolic and
residual amino proton NMR signals at 9.39 ppm and 9.92 ppm, respec-
tively, confirming mono-N-acylation, while the amide and ester carbonyl
carbons resonated at 165.2 ppm and 169.9 ppm, respectively, as deter-
mined from the correlations between corresponding proton and carbon
signals in the heteronuclear multiple bond correlation (HMBC) spec-
trum. 2,3,4,5,6-Pentaacetyl-N-(3-hydroxyphenyl)gluconamide 13 was iso-
lated successfully from the reaction between 3-aminophenol 6a and
pentacetylated gluconyl chloride.[12] The five acetyl methyl groups reso-
nated as a series of singlets, integrating for 15 protons, between 2.01
and 2.24 ppm in the 1H NMR spectrum, while in the 13C NMR spectrum,

2726
M. Mutorwa et al.
Figure 1. General approach to novel truncated ATP mimics.
Figure 2. The 400 1H NMR spectra of allylated derivatives 7, 8, and 9 in CDCl3.

3-Substituted Aniline Derivatives
2727
Scheme 2. Access to 3-substituted anilides.
coincidence of two of the methyl signals resulted in four carbon signals
corresponding to the five methyl carbons. High-resolution mass spectro-
metric (HRMS) analysis confirmed the formation of compound 13, with
the base peak corresponding to the molecular ion at m=z 497.450192.
2-Chloro-N-(3-hydroxyphenyl)acetamide 14a was obtained in 76%
yield, with the correlation between the NH proton and the carbonyl carbon
in the HMBC spectrum confirming acylation of the amino rather than the
phenolic group. Arbuzov phosphonation of compound 14a with triethyl
phosphite[13] afforded the diethyl phosphonate ester 15a in 48% yield. In
1
the respective H and 13C NMR spectra, the CH2P proton and carbon
nuclei resonate as doublets as a result of coupling to the 31P nucleus. Seren-
dipitously, the phosphonate ester 15a was selected as a trial substrate for a
preliminary protein NMR study of ligand binding to the DXP-
reductoisomerase enzyme of the malaria parasite Plasmodium faciparum
(PfDXR). The results of the saturation transfer difference (STD)[14]
NMR experiment clearly indicated binding of compound 15a to the pro-
tein, and the protein–ligand interaction was supported by in vitro inhibition
of Pf DXR. Thus, although the phosphonate ester 15 was prepared as a
potential Mtb-GS inhibitor, its capacity to inhibit Pf DXR prompted us
to explore the analogous systems 15b–g (Scheme 2) as novel antimalarials.
(In vivo hydrolysis of the ester moieties is expected to release the corre-
sponding phosphonic acids as the more active species.) Progress in this
ongoing study on the synthesis of further analogs and the results of
enzyme-binding and enzyme-inhibition assays will be published in due
course.
EXPERIMENTAL
1H, 13C, and 31P NMR experiments were conducted on Bruker AMX
400-MHz and Avance 600-MHz spectrometers. Chemical shifts are
reported relative to the residual protonated solvent signals.
Low-resolution mass spectra (LRMS) were recorded on Finnigan-MAT

2728
M. Mutorwa et al.
GCQ or LCQ mass spectrometers, and HRMS data were obtained by the
University of the Witwatersrand, University of the Northwest
(Potchefstroom), or Stellenbosch University. Compounds 14a–g[15–20]
and 15b[21] are known. Illustrative experimental procedures and
characterization data for new compounds are detailed next.
N-Allyl-(3-hydroxy)aniline 7, N-Allyl-3-(allyloxy)aniline 8,
and N,N-Diallyl-3-hydroxyaniline 9
NaH (60% dispersion in mineral oil; 1.1 g, 28 mmol) was added in small
portions to a stirred solution of 3-aminophenol 6a (3.0 g, 28 mmol) in dry
tetrahydrofuran (THF) (30 mL) under nitrogen to permit controlled evo-
lution of hydrogen. Allyl bromide (2.4 mL, 28 mmol) was then added
through a septum, and the resulting solution was refluxed for ca. 4.5 h.
The reaction was quenched by the addition of water (50 mL). The organic
solvent was evaporated in vacuo, and the aqueous residue was extracted
with EtOAc (2 ꢀ 50 mL). The combined organic extracts were washed
sequentially with water (2 ꢀ 100 mL) and brine (2 ꢀ 100 mL). The aqu-
eous washings were extracted with EtOAc, and the organic layers were
combined and dried (anhydr. MgSO4). Flash chromatography [on silica
gel; elution with hexane–EtOAc (8:2)] afforded three fractions.
N-Allyl-(3-hydroxy)aniline 7
Dark brown oil (680 mg, 17%) (found: Mþ 149.083104; C9H11NO
requires M 149.084064); nmax (thin film=cmꢁ1) 3388 (NH); dH=ppm
(400 MHz; CDCl3) 3.70 (2H, dt, J ¼ 5.4 and 1.6 Hz, 10-CH2), 5.16 (1H,
qd, J ¼ 10.3 and 1.4 Hz, CH¼CHZ), 5.26 (1H, qd, J ¼ 17.2 and 1.6 Hz,
CH¼CHE), 5.92 (1H, m, 20-H), 6.10 (1H, t, J ¼ 2.3 Hz, 2-H), 6.20 (1H,
dd, J ¼ 8.0 and 2.3 Hz, 6-H), 6.23 (1H, dd, J ¼ 8.1 and 2.1 Hz, 4-H),
and 7.02 (1H, t, J ¼ 8.0 Hz, 5-H); dC=ppm (100 MHz; CDCl3) 46.6
(C-10), 100.3 (C-2), 105.0 (C-6), 106.2 (C-4), 116.4 (C-30), 130.1 (C-5),
135.1 (C-20), 149.4 (C-1), and 156.6 (C-3).
N-Allyl-3-(allyloxy)aniline 8
Dark brown oil (270 mg, 5.2%) (found: Mþ 189.115840; C12H15NO
requires M 189.115364); nmax (thin film=cmꢁ1) 3406 (NH2); dH=ppm
(400 MHz; CDCl3) 3.77 (2H, dt, J ¼ 5.4 and 1.6 Hz, 10-CH2), 4.51 (2H,
td, J ¼ 5.3 and 1.5 Hz, 100-CH2), 5.18 (1H, m, 30-Ha), 5.30 (2H, m,

3-Substituted Aniline Derivatives
2729
30-Hb and 300-Ha), 5.42 (1H, m, 300-Hb), 5.97 (1H, m, 20-H), 6.07 (1H, m,
200-H), 6.23 (1H, t, J ¼ 2.3 Hz, 2-H), 6.26 (1H, dd, J ¼ 8.0 and 2.2 Hz,
6-H), 6.31 (1H, dd, J ¼ 8.1 and 2.3 Hz, 4-H), and 7.08 (1H, t, J ¼ 8.1 Hz,
Hz, 5-H); dC=ppm (100 MHz; CDCl3) 46.5 (C-10), 68.6 (C-100), 99.7 (C-2),
103.4 (C-4), 106.3 (C-6), 116.1 (C-30), 117.3 (C-300), 129.8 (C-5), 133.5
(C-200), 135.3 (C-20), 149.4 (C-1), and 159.8 (C-3).
N,N-Diallyl-3-(hydroxy)aniline 9
Dark brown oil (830 mg, 16%) (found: Mþ 189.114166, C12H15NO
requires M 189.115364); nmax (thin film=cmꢁ1) 3363 (NH); dH=ppm
(400 MHz; CDCl3) 3.89 (4H, m, 10-CH2 and 100-CH2), 5.18 (4H, m,
30-CH2 and 300-CH2), 5.85 (2H, m, 20-H and 200-H), 6.19 (1H, m, 6-H),
6.22 (1H, s, 2-H), 6.32 (1H, m, 4-H), and 7.06 (1H, t, J ¼ 8.1 Hz, 5-H);
dC=ppm (100 MHz; CDCl3) 52.7 (C-10 and C-100), 99.6 (C-2), 103.5
(C-6), 105.3 (C-4), 116.0 (C-30 and C-300), 129.9 (C-5), 133.8 (C-20 and
C-200), 150.2 (C-1) and 156.4 (C-3).
3-(Acrylamido)phenyl acrylate 10 and N-(3-hydroxyphenyl)acrylamide 11
NaH (60% dispersion in mineral oil; 0.11 g, 4.6 mmol) was added in small
portions to a stirred solution of 3-aminophenol 6a (0.50 mg, 4.6 mmol) in
dry THF (15 mL) under nitrogen to permit controlled evolution of hydro-
gen. Acryloyl chloride (0.37 mL, 4.6 mmol) was then added through a
septum, and the resulting solution was refluxed for ca. 6 h. The reaction
was quenched by the addition of water (20 mL). The organic solvent was
evaporated in vacuo, and the aqueous residue was extracted with EtOAc
(2 ꢀ 40 mL). The combined organic extracts were washed sequentially
with water (2 ꢀ 80 mL) and brine (2 ꢀ 80 mL). The aqueous washings
were extracted with EtOAc, and the organic layers were combined and
dried (anhydr. MgSO4). Preparative-layer chromatography [on silica
gel; elution with hexane–EtOAc (4:6)] afforded two fractions.
N-(3-Hydroxyphenyl)acrylamide 11
Yellow oil (5.4 mg, 0.72%) (found: Mþ 163.076095; C9H9NO2 requires M
163.063329); nmax (thin film=cmꢁ1) 3419 (OH) and 1667 (C¼O); dH=ppm
(400 MHz; CDCl3) 6.01 (1H, d, J ¼ 10.5 Hz, 30-Ha), 6.30 (1H, dd, J ¼ 17.3
and 10.5 Hz, 20-H), 6.60 (1H, d, J ¼ 17.3 Hz, 30-Hb), 6.89 (1H, d,
J ¼ 7.0 Hz), 7.34 (2H, m, 5-H and 6-H) and 7.50 (1H, s, 2-H); dC=ppm

2730
M. Mutorwa et al.
(150 MHz; CDCl3) 113.5 (C-2), 117.1 (C-6), 17.6 (C-4), 127.8 (C-20),
129.7 (C-5), 132.9 (C-30), 138.5 (C-1), 150.9 (C-3) 164.6 and 167.7
(C¼O).
3-(Acrylamido)phenyl acrylate 10
Yellow oil (12 mg, 1.2%) (found: Mþ 217.072324; C12H11NO3 requires M
217.073893); nmax (thin film=cmꢁ1) 1731 (OC¼O) and 1663 (NHC¼O);
dH=ppm (400 MHz; CDCl3) 5.70 (1H, d, J ¼ 10.2 Hz, 300-Ha), 6.03 (1H,
d, J ¼ 10.4 Hz, 30-Ha), 6.16 (1H, dd, J ¼ 16.8 and 10.3 Hz, 200-H), 6.32
(2H, m, 20-H and 300-Hb), 6.60 (1H, d, J ¼ 17.3 Hz, 30-Hb), 6.82 (1H, d,
J ¼ 7.09 Hz, 6-H), 7.24 (2H, m, 4-H and 5-H), 7.58 (1H, s, 2-H) and
7.95 (1H, s, NH); dC=ppm (100 MHz; CDCl3) 113.5 (C-2), 117.2 (C-4),
117.3 (C-6), 127.7 (C-20), 127.9 (C-300), 129.6 (C-5), 130.9 (C-1), 133.1
(C-30), 139.1 (C-3), 150.7 (C-1), 163.7 (OC¼O), and 165.0 (NHC¼O).
2-Acetoxy-N-(3-hydroxyphenyl)acetamide 12
To permit controlled evolution of hydrogen NaH (60% dispersion in
mineral oil; 60 mg, 2.5 mmol) was added in small portions to a stirred
solution of 3-aminophenol 6a (150 mg, 1.4 mmol) in dry THF (10 mL)
under nitrogen at 0ꢂC. Acetoxyacetyl chloride (160 mL, 2.5 mmol) was
then added through a septum, and the resulting solution was refluxed
for ca. 5 h. The reaction was quenched by the addition of water
(20 mL). The organic solvent was evaporated in vacuo, and the aqueous
residue was extracted with EtOAc (2 ꢀ 40 mL). The combined organic
extracts were washed sequentially with water (2 ꢀ 80 mL) and brine
(2 ꢀ 80 mL). The aqueous washings were extracted with EtOAc, and
the organic layers were combined and dried (anhydr. MgSO4). Evapora-
tion of the solvent in vacuo and chromatography of the residue [flash
chromatography on silica; elution with EtOH–CHCl3–hexane
(0.5:1.5:2.5)] afforded 2-acetoxy-N-(3-hydroxyphenyl)acetamide 12 as a
grey powder (70 mg, 24%), mp 154–156ꢂC (found: Mþ 209.068446;
C10H11NO4 requires M 209.068808); nmax (solid deposit=cmꢁ1) 3424
(OH), 1734 (CH3C¼O) and 1678 (NHC¼O); dH=ppm (400 MHz;
DMSO-d6) 2.11 (3H, s, CH3), 4.61 (2H, s, CH2), 6.46 (1H, dd, J ¼ 7.9
and 2.2 Hz, 60-H), 6.93 (1H, d, J ¼ 8.3 Hz, 40-H), 7.07 (1H, t, J ¼ 8.06 Hz,
Hz, 50-H), 7.13 (1H, t, J ¼ 2.0 Hz, 20-H), 9.39 (1H, br s, OH) and 9.92
(1H, s, NH); dC=ppm (100 MHz; DMSO-d6) 20.4 (CH3), 62.5 (CH2),
106.3 (C-20), 109.9 (C-40), 110.5 (C-60), 129.3 (C-50), 139.3 (C-10), 157.5
(C-30), 165.2 (NHC¼O) and 169.9 (CH3C¼O).

3-Substituted Aniline Derivatives
2731
2,3,4,5,6-Pentaacetyl-N-(3-hydroxyphenyl)-D-gluconamide 13
NaH (60% dispersion in mineral oil; 0.041 g, 0.92 mmol) was added in
small portions to a solution of 3-aminophenol 6a (0.10 g, 0.92 mmol) in
pyridine (2 mL) to permit controlled evolution of hydrogen. 2,3,4,5,
6-Pentaacetyl-D-gluconoyl chloride[23] (0.40 g, 0.92 mmol) was then
added, and the reaction mixture was stirred at room temperature for
ca. 2.5 days. The solvent was evaporated in vacuo, and the residue was
dissolved in EtOAc (30 mL). This solution was washed with water
(2 ꢀ 30 mL) and brine (2 ꢀ 30 mL). The organic layer was then dried
(anhydr. MgSO4), and the solvent was evaporated in vacuo to afford a
reddish brown oil. Flash chromatography [on silica gel; elution with
hexane–EtOAc (4:6)] afforded 2,3,4,5,6-pentaacetyl-N-(3-hydroxyphenyl)-
D-gluconamide 13 as a reddish brown oil (93 mg, 20%) (found: Mþ
497.15132; C22H27NO12 requires M 497.45019); nmax (solid deposit=
cmꢁ1) 3427 (OH), 1740 (CH3C¼O) and 1605 (NHC¼O); dH=ppm
(400 MHz; CDCl3) 2.06 (12H, series of singlets, 4 ꢀ CO.CH3), 2.22 (3H,
s, 6-OCO.CH3), 4.12 (1H, dd, J ¼ 12.4 and 5.5 Hz, 6-Ha), 4.34 (1H, dd,
J ¼ 12.4 and 3.3 Hz, 6-Hb), 5.06 (1H, dt, J ¼ 5.9 and 3.4 Hz, 5-H), 5.34
(1H, d, J ¼ 5.4 Hz, 2-H), 5.47 (1H, dd, J ¼ 6.5 and 4.7 Hz, 4-H), 5.70
(1H, t, J ¼ 5.0 Hz, 3-H), 6.63 (1H, dd, J ¼ 8.1 and 2.0 Hz, 40-H), 6.81
(1H, dd, J ¼ 8.0 and 1.1 Hz, 60-H), 7.13 (1H, t, J ¼ 8.1 Hz, 50-H), 7.33
(1H, s, 20-H) and 8.10 (1H, s, NH); dC=ppm (100MHz; CDCl3) 20.4,
20.6, 20.66, and 20.72 (5ꢀ CO.CH3), 61.7 (C-6), 68.9 (C-3), 69.0 (C-5),
69.2 (C-4), 71.8 (C-2), 107.4 (C-20), 111.6 (C-60), 112.4 (C-40), 130.0
(C-50), 137.6 (C-30), 156.9 (C-10), 164.6 (NHC¼O), 169.6, 169.9, 170.0,
170.3, and 170.9 (5 ꢀ C¼O); m=z ¼ 496 (M ꢁ 1, 28%) and 412 (100).
2-Chloro-N-(3-hydroxyphenyl)acetamide 14a
NaH (60% dispersion in mineral oil; 1.2 g, 50 mmol) was added in small
portions to a stirred solution of 3-aminophenol 6a (3.0 g, 28 mmol) in
THF (30 mL) under nitrogen to permit controlled evolution of hydrogen.
Chloroacetyl chloride (2.2 mL, 28 mmol) was then added through a
septum, and the resulting solution was stirred for ca. 6 h. The solvent
was evaporated in vacuo, and the residue was dissolved in EtOAc
(2 ꢀ 50 mL). The organic extract was washed sequentially with satd. aq.
NaHCO3 (2 ꢀ 100 mL), water (2 ꢀ 100 mL), and brine (2 ꢀ 100 mL).
The aqueous washings were extracted with EtOAc, and the combined
organic solutions were dried (anhydr. MgSO4). Evaporation of the sol-
vent in vacuo afforded 2-chloro-N-(3-hydroxyphenyl)acetamide 14a as
a grey solid (3.9 g, 76%), mp 119–120ꢂC (lit.[16] 134.5–136ꢂC); nmax (solid

2732
M. Mutorwa et al.
deposit=cmꢁ1) 3360 (OH) and 1642 (C¼O); dH=ppm (400 MHz;
DMSO-d6) 4.22 (2H, s, CH2), 6.48 (1H, dd, J ¼ 8.0 and 2.0 Hz, 60-H),
6.94 (1H, d, J ¼ 8.5 Hz, 40-H), 7.09 (1H, t, J ¼ 8.1 Hz, 50-H), 7.17 (1H,
t, J ¼ 2.0 Hz, 20-H), 9.48 (1H, s, OH) and 10.18 (1H, s, NH); dC=ppm
(100 MHz; DMSO-d6) 43.6 (CH2), 106.3 (C-20), 110.0 (C-60), 110.9
(C-40), 129.5 (C-50), 139.5 (C-10), 157.6 (C-30), and 164.4 (C¼O).
Diethyl [N-(3-hydroxyphenyl)carbamoyl]methylphosphonate 15a
Triethyl phosphite (2.6 mL, 15 mmol) was added through a septum to
2-chloro-N-(3-hydroxyphenyl)acetamide 14a (500 mg, 30 mmol) in an
oven-dried, round-bottomed flask, equipped with a reflux condenser
under nitrogen. The resulting mixture was refluxed for ca. 9 h during
which time the reaction was monitored by thin-layer chromatography
(TLC). The cooled mixture was then stirred with hexane (20 mL) for
ca. 10 min followed by decantation of the hexane layer to remove the
excess phosphite; this was repeated twice. Evaporation of the solvent in
vacuo afforded diethyl [N-(3-hydroxyphenyl)carbamoyl]methylphospho-
nate 15a as white crystals (370 mg, 48%), mp 115–117ꢂC (found: Mþ
287.093363; C12H18NO5P requires M 287.092261); nmax (solid depos-
it=cmꢁ1) 3263 (OH), 1667 (C¼O), and 1230 (P¼O); dH=ppm (400 MHz;
CDCl3) 1.32 (6H, t, J ¼ 6.8 Hz, 2 ꢀ CH3), 3.05 (2H, d, JP–H ¼ 21.1 Hz,
1-CH2), 4.17 (4H, m, 2 ꢀ CH3CH2), 6.60 (1H, d, J ¼ 8.0 Hz, 40-H), 6.80
(1H, d, J ¼ 7.9 Hz, 60-H), 7.09 (1H, t, J ¼ 8.0 Hz, 50-H), 7.46 (1H, s,
20-H), 7.99 (1H, s, OH) and 8.96 (1H, s, NH); dC (100 MHz; CDCl3)
16.3 (d, JP–C ¼ 6.0 Hz, 2 ꢀ CH3), 36.4 (d, JP–C ¼ 130.4 Hz, 1-CH2), 63.3
(d, JP–C ¼ 6.6 Hz, 2 ꢀ CH3CH2), 107.3 (C-20), 111.1 (C-60), 112.1 (C-40),
129.8 (C-50), 138.5 (C-10), 157.3 (C-30) and 162.7 (d, JPꢁC ¼ 4.1 Hz,
C¼O); dP=ppm (162 MHz; CDCl3) 24.2 (P¼O).
Other Analytical Data
Diethyl [N-(3-bromophenyl)carbamoyl]methylphosphonate 15c
Yellowish-brown solid (0.25 g, 62%), mp 73–75ꢂC; tmax (solid deposit=
cmꢁ1) 1683 (C¼O) and 1238 (P¼O); dH=ppm (400 MHz; CDCl3) 1.34
(6H, t, J ¼ 6.8 Hz, 2 ꢀ CH3), 1.64 (1H, s, OH) 3.01 (2H, d, JP–H ¼ 20.4 Hz,
Hz, 1-CH ), 4.17 (4H, m, 2 ꢀ CH3CH2), 6.63 (1H, d, J ¼ 8.4 Hz, 40-H),
2
7.01 (1H, d, J ¼ 8.0 Hz, 60-H), 7.18 (1H, t, J ¼ 8.0 Hz, 50-H), 7.23 (1H, s,
20-H), and 8.83 (1H, s, NH); dC (100 MHz; CDCl3) 16.3 (d, JP–C ¼ 5.7 Hz,
2 ꢀ CH3), 35.6 (d, JP–C ¼ 129.1 Hz, 1-CH2), 63.0 (d, JP–C ¼ 6.6 Hz,

3-Substituted Aniline Derivatives
2733
2 ꢀ CH3CH2), 112.4 (C-20), 117.8 (C-60), 122.3 (C-40), 126.8 (C-50), 129.8
(C-10), 139.2 (C-30) and 162.2 (d, JPꢁC ¼ 4.4 Hz, C¼O).
Diethyl [N-(3-fluorophenyl)carbamoyl]methylphosphonate 15d
Brown solid (0.26 g, 56%), mp 83–85ꢂC (found: Mþ 289.086707.
C12H17FNO4P requires M 289.239842); tmax (solid deposit=cmꢁ1) 1680
(C¼O) and 1228 (P¼O); dH=ppm (400 MHz; CDCl3) 1.35 (6H, t,
J ¼ 7.2 Hz, 2 ꢀ CH3), 1.65 (1H, s, OH) 3.04 (2H, d, JP–H ¼ 20.8 Hz,
1-CH2), 4.17 (4H, m, 2 ꢀ CH3CH2), 6.73 (1H, t, J ¼ 8.0 Hz, 40-H), 7.09
(1H, d, J ¼ 8.4 Hz, 60-H), 7.16 (1H, t, J ¼ 6.4 Hz, 50-H), 7.44 (1H, d,
J ¼ 11.2 Hz, 20-H), and 9.23 (1H, s, NH); dC (100 MHz; CDCl3) 16.3
(d, JP–C ¼ 6.0 Hz, 2 ꢀ CH3), 35.5 (d, JP–C ¼ 127 Hz, 1-CH2), 63.0 (d, JP–
¼ 6.5 Hz, 2 ꢀ CH3CH2), 107.0 (C-20), 111.0 (C-60), 114.9 (C-40), 129.8
C
(C-50), (C-10), 162.1 (C-30), and 164.0 (C¼O).
Diethyl [N-(3-cyanophenyl)carbamoyl]methylphosphonate 15e
Yellowish-brown solid (0.21 g, 48%), mp 83–85ꢂC (found: Mþ
296.090709; C13H17N2O4P requires M 296.258840); tmax (solid depos-
it=cmꢁ1) 1686 (C¼O) and 1217 (P¼O); dH=ppm (400 MHz; CDCl3)
1.37 (6H, t, J ¼ 7.2 Hz, 2 ꢀ CH3), 3.01 (2H, d, JP–H ¼ 20.8 Hz, 1-CH2),
4.19 (4H, q, J ¼7.6 Hz, 2 ꢀ CH3CH2), 7.30 (2H, d, J ¼5.6 Hz, 40-H and
60-H), 7.59 (1H, m, 50-H), 7.93 (1H, s, 20-H), and 9.50 (1H, s, NH); dC
(100 MHz; CDCl3) 16.3 (d, JP–C ¼ 6.0 Hz, 2 ꢀ CH3), 36.9 (d, JP–C ¼ 129.3 Hz,
, 1-CH ), 63.3 (d, JP–C ¼ 7.2 Hz, 2 ꢀ CH3CH2), 112.6 (CꢃN), 118.4
2
(C-10), 122.4 (C-20), 123.2 (C-60), 127.2 (C-40), 129.4 (C-50), 138.8 (C-30)
and 162.5 (C¼O).
Diethyl [N-(3-nitrophenyl)carbamoyl]methylphosphonate 15f
Dark brown oil (0.42 g, 72%) (found: Mþ 316.082395; C12H17N2O6P
requires M, 316.247489); tmax (thin film=cmꢁ1) 1684 (C¼O) and 1262
(P¼O); dH=ppm (400 MHz; CDCl3) 1.36 (6H, t, J ¼ 7.2 Hz, 2 ꢀ CH3),
3.06 (2H, d, JP–H ¼ 21.2 Hz, 1-CH2), 4.20 (4H, q, J ¼ 7.6 Hz,
2 ꢀ CH3CH2), 7.29 (1H, t, J ¼ 8.4 Hz, 50-H), 7.85 (1H, m, 40-H and
60-H), 8.29 (1H, s, 20-H), and 9.87 (1H, s, NH); dC (100 MHz; CDCl3)
16.3 (d, JP–C ¼ 6.2 Hz, 2 ꢀ CH3), 35.6 (d, JP–C ¼ 128.2 Hz, 1-CH2),
63.6 (d, JP–C ¼ 5.8 Hz, 2 ꢀ CH3CH2), 114.1 (C-20), 118.5 (C-60), 124.8
(C-40), 124.9 (C-50), 129.5 (C-10), 139.1 (C-30), and 162.6 (C¼O).

2734
M. Mutorwa et al.
Diethyl {N-[3-(hydroxymethyl)phenyl]carbamoyl}methylphosphonate 15g
Yellow oil (0.29 g, 65%) (found: Mþ 301.108030; C13H20NO5P requires
M 301.275361); tmax (solid deposit=cmꢁ1) 3274 (OH), 1684 (C¼O), and
1376 (P¼O); dH=ppm (400 MHz; CDCl3) 1.35 (6H, t, J ¼ 6.8 Hz,
2 ꢀ CH3), 2.03 (1H, s, OH), 3.01 (2H, d, JP–H ¼ 21.2 Hz, 1-CH2), 4.18
(4H, q, J ¼ 7.2 Hz, 2 ꢀ CH3CH2), 4.59 (2H, s, 7-CH2OH), 7.00 (1H, d,
J ¼ 7.6 Hz, 40-H), 7.20 (1H, t, J ¼ 8.0 Hz, 50-H), 7.42 (1H, s, 20-H), 7.45
(1H, d, 8.0 Hz, 60-H), and 9.20 (1H, s, NH); dC (100 MHz; CDCl3),
16.3 (d, JP–C ¼ 5.8 Hz, 2 ꢀ CH3), 36.7 (d, JP–C ¼ 128.4 Hz, 1-CH2), 63.0
(d, JP–C ¼ 7.2 Hz, 2 ꢀ CH3CH2), 64.7 (C-7), 118.1 (C-20), 118.7 (C-60),
122.6 (C-40), 128.9 (C-50), 138.0 (C-10), 141.9 (C-30), and 163.5 (C¼O).
ACKNOWLEDGMENTS
The authors thank the Medical Research Council of South Africa, the
Innovation Fund Programme of the South African Department of
Science and Technology, and Rhodes University for generous financial
support.
REFERENCES
1. Beers, M. H.; Berkow, R. The Merck Manual of Diagnosis and Therapy, 7th
ed.; Merck & Co., Inc.: Whitehouse Station, NJ, 1999; p. 1193; (b) Kim, J. Y.;
Shakow, A.; Mate, K.; Vanderwarker, C.; Gupta, R.; Farmer, P. Limited
good and limited vision: Multidrug-resistant tuberculosis and global health
policy. Soc. Sci. Med. 2005, 61 (4), 847–859.
´
´
2. Raynaud, C.; Etienne, G.; Peyron, P.; Laneelle, M.; Daffe, M. Extracellular
enzyme activities potentially involved in the pathogenicity of Mycobacterium
tuberculosis. Microbiology 1998, 144, 577–587.
3. Harth, G.; Horwitz, M. A. Expression and efficient export of enzymically
active Mycobacterium tuberculosis glutamine synthetase in Mycobacterium
smegmatis and evidence that the information for export is contained within
the protein. J. Biol. Chem. 1997, 272 (36), 22728–22735.
4. Harth, G.; Horwitz, M. A. J. An inhibitor of exported Mycobacterium tuber-
culosis glutamine synthetase selectively blocks the growth of pathogenic
mycobacteria in axenic culture and in human monocytes: Extracellular
proteins as potential novel drug targets. Exp. Med. 1999, 189 (9), 1425–1435.
5. Harth, G.; Clemens, D. L.; Horwitz, M. A. Glutamine synthetase of
Mycobacterium tuberculosis: Extracellular release and characterization of its
enzymic activity. Proc. Natl. Acad. Sci. USA 1994, 91 (20), 9342–9346.
6. Hirschfield, G. R.; McNeil, M.; Brennan, P. J. Peptidoglycan-associated
polypeptides of Mycobacterium tuberculosis. J. Bacteriol. 1990, 172 (2),
1005–1013.

3-Substituted Aniline Derivatives
2735
7. Eisenberg, D.; Gill, H. S.; Pfluegl, G. M. U.; Rotstein, S. H. Structure–
function relationships of glutamine synthetases. Biochim. Biophys. Acta.
2000, 1477 (1–2), 122–145.
8. Salisu, S. T. ATP Mimics as Glutamine Synthetase Inhibitors—An Exploratory
Synthetic Study (PhD Thesis, Rhodes University, 2008).
9. Jomaa, H.; Wiesner, J.; Sanderbrand, S.; Altincicek, B.; Weidemeyer, C.;
Hintz, M.; Turbachova, I.; Eberl, J.; Zeidler, J.; Lichtenthaler, H. K.;
Soldati, D.; Beck, E. Inhibitors of the nonmevalonate pathway of isoprenoid
biosynthesis as antimalarial drugs. Science 1999, 285 (5433), 1573–1576.
10. Reichenberg, A.; Wiesner, J.; Weidemeyer, C.; Dreiseidler, E.; Sanderbrand,
S.; Altincicek, B.; Beck, E.; Schlitzer, M.; Jomaa, H. Diaryl ester prodrugs of
FR900098 with improved in vivo antimalarial activity. Bioorg. Med. Chem.
Lett. 2001, 11 (6), 833–835.
11. HOSE code prediction. http://www.modgraph.co.uk/product_nmr-HOSE.
htm (accessed December 20, 2007).
12. Robins, M. J.; Hatfield, P. W. Nucleic acid related compounds, 38: Smooth
and high-yield iodination and chlorination at C-5 of uracil bases and p-
tolyl-protected nucleosides. Can. J. Chem. 1982, 60 (5), 547–553.
13. Thomas, B. N.; Lindermann, C. M.; Corcoran, R. C.; Cotant, C. L.; Kirsch,
J. E.; Persichini, P. J. Phosphonate lipid tubules II. J. Am. Chem. Soc. 2002,
124 (7), 1227–1233.
14. Uhrin, D.; Prasad, A. V. K.; Brisson, J.; Bundle, D. R. Carbohydrate–anti-
body interactions by NMR for a 13C-labeled disaccharide ligand. Can. J.
Chem. 2002, 80 (8), 904–907.
15. Jacobs, W. A.; Heidelberger, M. The quaternary salts of hexamethylenetetra-
mine, III: Monohalogenacylated aromatic amines and their hexamethylenete-
traminium (hexamethylenetetrammonium) salts. J. Bio. Chem. 1915, 21,
103–143.
16. Matulenko, M. A.; Hakeem, A. A.; Kolasa, T.; Nakane, M.; Terranova,
M. A.; Uchic, M. E.; Miller, L. N.; Chang, R.; Donnelly-Roberts, D. L.;
Namovic, M. T.; Moreland, R. B.; Brioni, J. D.; Stewart, A. O. Synthesis
and functional activity of (2-aryl-1-piperazinyl)-N-(3-methylphenyl)aceta-
mides: Selective dopamine D4 receptor agonists. Bioorg. Med. Chem. 2004,
12 (13), 3471–3483.
17. Khanna, S.; Madan, M.; Vangoori, A.; Banerjee, R.; Thaimattam, R.; Basha,
S. K. J. S.; Ramesh, M.; Casturi, S. R.; Pal, M. Evaluation of glycolamide
esters of indomethacin as potential cyclooxygenase-2 (COX-2) inhibitors.
Bioorg. Med. Chem. 2006, 14 (14), 4820–4833.
18. Bhatia, P. A.; Daanen, J. F.; Hakeem, A. A.; Kolasa, T.; Matulenko, M. A.;
Mortell, K. H.; Patel, M. V.; Stewart, A. O.; Wang, X.; Xia, Z.; Zhang, H. Q.
Preparation of piperazinyl, piperidinyl, and related acetamides and
benzamides as dopamine D4 receptor agonists useful in treating sexual
dysfunction. U.S. Pat. Appl. Publ., US2004029887 A1 20040212, 2004.
Cont.-in-part of U.S. Ser. No. 154,373.
19. Desai, A. D.; Chikhalia, K. H. Synthesis and studies of N-aryl-2-[4-
(4-methyl-1-piperazinyl)anilino]acetamides. E-J. Chem. 2005, 2 (6), 15–20.

2736
M. Mutorwa et al.
20. Nakao, N.; Ohashi, K.; Ogihara, T.; Okano, A.; Matsumura, Y.; Nakano, T.
Therapeutic agent for urinary incontinence. PCT Int. Appl., WO 2003063852
A1 20030807, 2003.
21. Ando, K.; Tsuji, E.; Ando, Y.; Kunitomo, J.-I.; Kobayashi, R.; Yokomizo,
T.; Shimizu, T.; Yamashita, M.; Ohta, S.; Nabe, T.; Kohno, S.; Ohishi, Y.
Synthesis of 2-, 4-, and 5-(2-alkylcarbamoyl-1-methylvinyl)-7-alkyloxyben-
zo[b]furans and their leukotriene B4 receptor antagonistic activity. Org.
Biomol. Chem. 2005, 3 (11), 2129–2139.
22. Braune, C. E.; Cook, C. D. 2,3,4,5,6-Penta-O-acetyl-D-gluconic acid and
2,3,4,5,6-penta-O-acetyl-d-gluconyl chloride. Org. Synth. 1961, 41, 79–82.