# Thioxopyrimidine in Heterocyclic Synthesis III: Synthesis and Properties of Some Novel Heterocyclic Chalcone Derivatives Containing a Thieno[2,3-d]pyrimidine-Based Chromophore

Authors: Yuh Wen Ho; Wei Hua Yao
Journal: Journal of Chemistry
 (2013)

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## Abstract

Cyclization of 4-methyl-2-phenyl-6-thioxo-1,6-dihydropyrimidine-5-carbonitrile1 with chloroacetone in DMF in the presence of excess potassium carbonate anhydrous gave the 1-(5-amino-4-methyl-2-phenylthieno[2,3-d]pyrimidin-6-yl)ethanone 3, which can react with 2,5-dimethoxytetrahydrofuran in glacial acetic acid producing the 1-[4-methyl-2-phenyl-5-(1H-pyrrol-1-yl)thieno[2,3-d]pyrimidin-6-yl]ethanone 4. On the other hand, a series of novel 3-aryl-1-[4-methyl-2-phenyl-5-(1H-pyrrol-1-yl)-thieno[2,3-d]pyrimidin-6-yl]prop-2-en-1-one chalcone dyes 6a—n were obtained by the condensation reaction of 1-[4-methyl-2-phenyl-5(1H-pyrrol-1-yl)thieno[2,3-d]-pyrimidin-6-yl]ethanone 4 with appropriate aldehydes. The structures of chalcone dyes were characterized by IR, 1H NMR, mass, elemental analysis, and UV-Vis spectroscopy. The dyes were applied to polyester fibers for creating hues ranging from greenish-yellow to orange; their spectral characteristics, substituent effect in DMF solution, fastness properties, and colorimetric assessment are also discussed.


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## Body

## 1. Introduction

The considerable biological and medicinal activity caused by fused thienopyrimidines has stimulated much research in this field [1–5]. Moreover, several series of heterocyclic compounds possessing a bridgehead pyrrolic moiety play a vital role in many biological activities [6–10]. Likewise, compounds with a chalcone-based structure have showed an array of pharmacological activities [11–16]. However, chalcones, the bichromophoric molecules separated by vinyl chains and the carbonyl group, are found being effective photosensitive materials and exhibit promising nonlinear optical properties [17]. On the other hand, molecular two-photon absorption (TPA) has attracted a lot of interest recently for its applications in the field of both biological imaging and materials science; TPA materials have recently received considerable attention [18–20]. A number of organic molecules have been studied for TPA activity [21–24]. Among these TPA systems, the heterocycle-based chromophores are particularly interesting due to their easily polarizable heteroaromatic rings which can help to improve their degree of intramolecular charge transfer (ICT) [25–27]. Recently the synthesis and characterization of chromophores have been reported in which the donor moiety is represented by a π-excessive five-membered heterocycle (pyrrole or thiophene) and the acceptor group is a deficient heterocyclic azine ring (pyridine, pyrazine, pyrimidine, and pyridazine), which exhibit solvatochromic, electrochromic, photochromic, fluorescent, and nonlinear optical properties [28, 29]. Further developments involve the stretch of the charge transfer and the length of the π-bridge, such as multibranched octupoles or dendrimers [30].Beyond these very important applications in biological chemistry, the chalcones are also found being used in the production of nematic liquid crystals [31], photosensitive polymers [32], antioxidants [33, 34], and as dyes [35, 36]. Although a number of papers concerning the synthesis of chalcone compounds have been published, those containing a new heterocyclic system of thieno[2,3-d]-pyrimidine-based chromophores and application have not yet been reported. Therefore, based on our previous works [37–39], we aim to report herein the preparation of a series of chalcone derivatives containing a thieno[2,3-d]-pyrimidine-based chromophore, and there was application to polyester fibers as disperse dyes. The spectral characteristics, dyeing properties, and colorimetric assessment of the dyes are also discussed.


## 2. Experimental

### 2.1. General

All melting points are uncorrected and in °C. IR spectra were recorded on a JASCO FTIR-3 spectrometer (KBr);1H NMR spectra were obtained on a Bruker AM-300 WB FI-NMR spectrometer, and chemical shifts are expressed in δ ppm using TMS as an internal standard. Electron impact mass spectra were obtained at 70 eV using a Finnigan Mat TSQ-46C spectrometer. Elemental analyses were performed on a Perkin-Elmer 240 elemental Analyzer. Electronic spectra were recorded on a Shimadzu UV 240 from dye solutions in DMF at a concentration of 2 × 10−5 mol L−1. Aldehydes 5a–n were purchased from Aldrich and were used without further purification.


### 2.2. Synthesis of 1-(5-Amino-4-methyl-2-phenylthieno[2,3-d]pyrimidin-6-yl)ethanone (3)

To a solution of 4-methyl-2-phenyl-6-thioxo-1,6-dihydropyrimidine-5-carbo-nitrile1 (2.27 g, 0.01 mol) in DMF (50 mL), potassium carbonate anhydrous (2.76 g, 0.02 mol) and chloroacetone 2 (0.93 g, 0.01 mol) were added. The reaction mixture was stirred at room temperature for 4 h and then diluted with cold water (50 mL). The resulting solid product was collected by filtration, washed with water, and recrystallized from ethyl acetate/ethanol to give 2.66 g of yellow needles (94% yield), m.p. 210°C; IR: ν 3424, 3295 (NH2), 1663 (C=O) cm−1; 1H NMR (CDCl3): δ 2.47 (3H, s, COCH3), 3.07 (3H, s, CH3), 3.76 (2H, br, NH2), 8.58–8.55, 7.60–7.55 (5H, m, phenyl-H); MS: 283 (M+, 100),268 (95), 240 (20), 212 (2), 165 (5), 160 (10), 137 (34), 110 (18), 77 (9). Anal. Calcd. for C15H13N3OS: C, 63.60; H, 4.59; N, 14.84. Found: C, 63.63; H, 4.50; N, 14.77%.


### 2.3. Synthesis of 1-[4-Methyl-2-phenyl-5-(1H-pyrrol-1-yl)thieno[2,3-d]pyrimidin-6-yl]ethanone (4)

A mixture of 1-(5-amino-4-methyl-2-phenylthieno[2,3-d]pyrimidin-6-yl)ethan-one 3 (2.83 g, 0.01 mol), 2,5-dimethoxytetrahydrofuran (1.26 g, 0.01 mol), in glacial acetic acid (20 mL) was refluxed for 12 h. After cooling, the resulting solid product was collected by filtration, washed with water, and the crude product recrystallized from ethanol/glacial acetic acid to give 2.96 g of gray white needles (89% yield), m.p. 204°C; IR: ν 1660 (C=O) cm−1; 1H NMR (CDCl3): δ 2.09 (3H, s, COCH3), 2.20 (3H, s, CH3), 6.50 (2H, t, 3,4-H of pyrrolyl), 6.87 (2H, t, 2,5-H of pyrrolyl), 8.56–8.54, 7.51–7.49 (5H, m, phenyl-H); MS: 333 (M+, 100), 318 (35), 290 (36), 277 (4), 223 (4), 185 (8), 166 (10), 160 (14), 116 (10), 103 (20), 77 (19), 51 (5). Anal. Calcd. for C19H15N3OS: C, 68.46; H, 4.50; N, 12.61. Found: C, 68.33; H, 4.52; N, 12.59%.


### 2.4. Synthesis of 3-Aryl-1-[4-methyl-2-phenyl-5(1H-pyrrol-1-yl)thieno[2,3-d]pyrimidin-6-yl]prop-2-en-1-ones (6a–n) General Procedure

A mixture of compound4 (0.33 g, 1.0 mmol), appropriate aldehydes 5a-n (1.0 mmol) and NaOH (2.2 mmol) in absolute ethanol (10 mL) was stirred at room temperature for 24 h. The mixture was stirred at room temperature for 24 h. The mixture was acidified with dilute acetic acid, and the precipitated product was collected by filtration, washed with water, and the crude product recrystallized from THF/ethanol. The physical constants and spectral data of compounds 6a–n are recorded in Tables 1 and 2.Table 1
Physical and analytical data of 6-(3-substituted-acryloyl)-5-(1-pyrrolyl)-4-methyl-2-phenylthieno[2,3-d]pyrimidine derivatives 6a–n.
Elemental analysis (%)
Dye
M.P.(°C)a
Yield(%)
Molecularformula
Calcd/Found
C
H
N
6a
184
88
C
26
H
18
Cl
N
3
OS
68.49
3.95
9.22
68.55
4.02
9.33
6b
282
96
C
28
H
24
N
4
OS
72.41
5.17
12.06
72.58
5.21
12.12
6c
170
96
C
27
H
21
N
3
OS
74.48
4.82
9.65
74.44
4.92
9.55
6d
262
95
C
27
H
21
N
3
O
2
S
71.84
4.65
9.31
71.80
4.71
9.45
6e
230
93
C
30
H
28
N
4
OS
73.17
5.69
11.38
73.22
5.74
11.24
6f
148
95
C
32
H
23
N
3
OS
77.26
4.62
8.45
77.23
4.77
8.56
6g
130
92
C
24
H
17
N
3
O
2
S
70.07
4.13
10.21
70.15
4.22
10.36
6h
262
98
C
24
H
17
N
3
O
S
2
67.44
3.98
9.83
67.39
4.06
9.89
6i
278
95
C
36
H
23
N
3
OS
79.26
4.22
7.70
79.58
4.56
7.98
6j
178
98
C
34
H
26
N
4
OS
75.83
4.83
10.40
75.88
4.73
10.33
6k
152
93
C
29
H
25
N
3
OS
75.16
5.40
9.07
75.18
5.42
9.24
6l
210
84
C
28
H
22
N
4
O
2
S
70.29
4.60
11.71
70.32
4.56
11.55
6m
228
90
C
34
H
23
N
3
OS
78.31
4.41
8.06
78.29
7.48
7.97
6n
286
94
C
38
H
28
N
4
OS
77.55
4.76
9.52
77.68
4.82
9.52
aRecrystallization from DMF/ethanol.Table 2
Spectra data of 6-(3-substituted-acryloyl)-5-(1-pyrrolyl)-4-methyl-2-phenyl-thieno[2,3-d]pyrimidine derivatives 6a–n.
MS
IR
1H-NMRa
Dye
(m/e M+)
(KBr)
(CF3COOD)
ν (cm−1)
δ (ppm)
6a
455.5
1667 (C=O)
2.20 (3H, s, CH3), 5.80 (1H, d, J=3.1Hz, COCH=), 6.62 (2H, m, 3,4-H of pyrrolyl), 6.87 (2H, m, 2,5-H of pyrrolyl), 6.75 (2H, d, J=1.00Hz, 3,5-H of phenyl), 7.33 (2H, d, J=1.00Hz, 2,6-H of phenyl), 7.82 (1H, d, J=3.1Hz, =CH–), 8.57–8.55, 7.55–7.21 (5H, m, phenyl-H)
6b
464
1628 (C=O)
2.27 (3H, s, CH3), 3.06 (6H, s, N(CH3)2), 5.70 (1H, d, J=3.1Hz, COCH=), 6.59–6.50 (2H, m, 3,4-H of pyrrolyl), 6.98–6.87 (2H, m, 2,5-H of pyrrolyl), 6.70 (2H, d, J=1.0Hz, 3,5-H of phenyl), 7.25 (2H, d, J=1.5Hz, 2,6-H of phenyl), 7.75 (1H, d, J=3.1Hz, =CH–), 8.57–8.54, 7.51–7.50 (5H, m, phenyl-H).
6c
435
1663 (C=O)
2.27 (3H, s, CH3), 2.39 (3H, s, CH3), 6.02 (1H, d, J=3.0Hz, COCH=), 6.61–6.51 (2H, m, 3,4-H of pyrrolyl), 7.09–6.87 (2H, m, 2,5-H of pyrrolyl), 7.79 (1H, d, J=3.0Hz, =CH–), 8.59–8.58, 7.81–7.33 (9H, m, phenyl-H).
6d
451
1668 (C=O)
2.33 (3H, s, CH3), 3.84 (3H, s, OCH3), 5.75 (1H, d, J=3.1Hz, COCH=), 6.60 (2H, t, 3,4-H of pyrrolyl), 6.87 (2H, d, J=1.0Hz, 3,5-H of phenyl), 6.99 (2H, t, 2,5-H of pyrrolyl), 7.28 (2H, d, J=1.0Hz, 2,6-H of phenyl), 7.76 (1H, d, J=3.0Hz, =CH–), 8.59–8.55, 7.52–7.51 (5H, m, phenyl-H).
6e
492
1628 (C=O)
1.21 (6H, t,J=1.4Hz, CH3), 2.27 (3H, s, CH3), 3.41 (4H, q, J=1.4Hz, CH2), 5.68 (1H, d, J=3.1Hz, COCH=), 6.59–6.49 (4H, m, 3,4-H of pyrrolyl and 3,5-H of phenyl), 6.98–6.87 (2H, m, 2,5-H of pyrrolyl), 7.24 (2H, d, J=1.0Hz, 2,6-H of phenyl), 7.74 (1H, d, J=3.0Hz, =CH–), 8.56–8.53, 7.50–7.49 (5H, m, phenyl-H).
6f
497
1667 (C=O)
2.18 (3H, s, CH3), 5.75 (1H, d, J=3.0Hz, COCH=), 6.50 (2H, t, 3,4-H of pyrrolyl), 6.86 (2H, t, 2,5-H of pyrrolyl), 8.65–8.54, 7.63–7.38 (15H, m, =CH– and phenyl-H).
6g
411
1667 (C=O)
2.28 (3H, s, CH3), 5.88 (1H, d, J=3.1Hz, COCH=), 6.59–6.48 (3H, m, 3,4-H of pyrrolyl and 4-H of furyl), 6.87 (2H, m, 2,5-H of pyrrolyl), 7.00 (1H, d, J=2.0Hz, 3-H of furyl), 8.15 (1H, d, J=3.0Hz, =CH–), 8.63–8.54, 7.58–7.48 (6H, m, 5-H of furyl and phenyl-H).
6h
427
1641 (C=O)
2.11 (3H, s, CH3), 5.47 (1H, d, J=3.2Hz, COCH=), 6.63–6.39 (3H, m, 3,4-H of pyrrolyl and 4-H of thienyl), 7.06–7.03 (2H, m, 2,5-H of pyrrolyl), 7.13 (1H, d, J=1.0Hz, 3-H of thienyl), 7.80 (1H, d, J=3.0Hz, =CH–), 8.48–8.45, 7.54–7.44 (6H, m, 5-H of thienyl and phenyl-H).
6i
545
1623 (C=O)
2.06 (3H, s, CH3), 5.79 (1H, d, J=3.1Hz, COCH=), 6.51 (2H, m, 3,4-H of pyrrolyl), 6.90 (2H, m, 2,5-H of pyrrolyl), 8.62–8.42, 8.32–8.05 (15H, m, =CH–, phenyl-H and pyrenyl-H).
6j
538
1633 (C=O)
1.77 (3H, t,J=1.2Hz, CH3), 2.52 (3H, s, CH3), 4.03 (2H, d, J=1.0Hz, CH2), 5.79 (1H, d, J=3.0Hz, COCH=), 6.51 (2H, m, 3,4-H of pyrrolyl), 6.90 (2H, m, 2,5-H of pyrrolyl), 8.72–7.61, (13H, m, =CH–, phenyl-H and carbazolyl-H).
6k
463
1643 (C=O)
2.10 (3H, s, CH3), 2.22 (6H, s, CH3), 2.28 (3H, s, CH3), 5.88 (1H, d, J=4.0Hz, COCH=), 6.51–6.45 (2H, m, 3,4-H of pyrrolyl), 6.88–6.84 (2H, m, 2,5-H of pyrrolyl), 7.39 (1H, d, J=1.2Hz, =CH–), 8.58–8.53, 7.54–7.51 (7H, m, phenyl-H).
6l
478
3324 (NH),1622 (C=O)
2.06 (3H, s, CH3), 2.16 (3H, s, COCH3), 5.78 (1H, d, J=3.0Hz, COCH=), 6.49 (2H, m, 3,4-H of pyrrolyl), 6.97 (2H, m, 2,5-H of pyrrolyl), 6.87 (2H, d, J=1.00Hz, 3,5-H of phenyl), 7.57 (1H, d, J=1.5Hz, =CH–), 8.50–8.29, 7.47–7.41 (7H, m, phenyl-H), 8.29 (1H, br, NH).
6m
521
1679 (C=O)
2.22 (3H, s, CH3), 6.13 (1H, d, J=3.0Hz, COCH=), 6.24 (2H, m, 3,4-H of pyrrolyl), 6.91 (2H, m, 2,5-H of pyrrolyl), 8.93–7.99, 7.54–7.26 (15H, m, =CH–, phenyl-H and anthracenyl-H).
6n
588
1631 (C=O)
2.30 (3H, s, CH3), 5.71 (1H, d, J=3.0Hz, COCH=), 6.55 (2H, t, 3,4-H of pyrrolyl), 6.98–6.94 (4H, m, 3,5-H of phenyl and 2,5-H of pyrrolyl), 7.74 (1H, d, J=3.0Hz, =CH–), 8.59–8.57, 7.53–7.13 (17H, m, phenyl-H).
as: Singlet; d: doublet; t: triplet; m: multiplet; br: broad.


### 2.5. Dyeing Procedure [40]

Polyester fabrics were dyed in a laboratory dyeing machine at a liquor ratio of 30 : 1. Dyebath (60 mL) was prepared with formulated dye and a dispersing agent (Diwatex 40, 0.5 g L−1) and adjusted to pH 4.0. The polyester fabric (2.0 g) was immersed in the dyebath and dyed for 60 min at 130°C. After dyeing, the dyed fabric was reduction cleared (Na2S2O4 2.0 g L−1, NaOH 2.0 g L−1, soaping agent 2.0 g L−1) for 20 min at 75°C.


### 2.6. Fastness Test

The light fastness was determined using standard procedures [41]. For sublimation fastness determinations, the dyed polyester fibers were stitched between two pieces of undyed polyester fibers (stain cloth) and treated at 200°C for 1 min. Any staining on the undyed piece, change in tone, or loss in depth was assessed on 1 (poor) to 5 (very good) rating.


### 2.7. Colorimetric Analysis

The color parameters of the dyed polyester fabrics were measured using the Applied Color System, CS-5 chroma-sensor, model 502 using D65 source and ultraviolet radiation [42]. Each fabric sample was folded twice so as to realize a total of four thicknesses of fabric. The assessment of color-dyed fabrics was made in terms of tristimulus colorimetry [43]. The CIE attributes of lightness (L*), chroma (C*), and hue (a* value represents the degree of redness (positive) and greenness (negative) and b* represents the degree of yellowness (positive) and blueness (negative)) were calculated in the present work.


## 2.1. General

All melting points are uncorrected and in °C. IR spectra were recorded on a JASCO FTIR-3 spectrometer (KBr);1H NMR spectra were obtained on a Bruker AM-300 WB FI-NMR spectrometer, and chemical shifts are expressed in δ ppm using TMS as an internal standard. Electron impact mass spectra were obtained at 70 eV using a Finnigan Mat TSQ-46C spectrometer. Elemental analyses were performed on a Perkin-Elmer 240 elemental Analyzer. Electronic spectra were recorded on a Shimadzu UV 240 from dye solutions in DMF at a concentration of 2 × 10−5 mol L−1. Aldehydes 5a–n were purchased from Aldrich and were used without further purification.


## 2.2. Synthesis of 1-(5-Amino-4-methyl-2-phenylthieno[2,3-d]pyrimidin-6-yl)ethanone (3)

To a solution of 4-methyl-2-phenyl-6-thioxo-1,6-dihydropyrimidine-5-carbo-nitrile1 (2.27 g, 0.01 mol) in DMF (50 mL), potassium carbonate anhydrous (2.76 g, 0.02 mol) and chloroacetone 2 (0.93 g, 0.01 mol) were added. The reaction mixture was stirred at room temperature for 4 h and then diluted with cold water (50 mL). The resulting solid product was collected by filtration, washed with water, and recrystallized from ethyl acetate/ethanol to give 2.66 g of yellow needles (94% yield), m.p. 210°C; IR: ν 3424, 3295 (NH2), 1663 (C=O) cm−1; 1H NMR (CDCl3): δ 2.47 (3H, s, COCH3), 3.07 (3H, s, CH3), 3.76 (2H, br, NH2), 8.58–8.55, 7.60–7.55 (5H, m, phenyl-H); MS: 283 (M+, 100),268 (95), 240 (20), 212 (2), 165 (5), 160 (10), 137 (34), 110 (18), 77 (9). Anal. Calcd. for C15H13N3OS: C, 63.60; H, 4.59; N, 14.84. Found: C, 63.63; H, 4.50; N, 14.77%.


## 2.3. Synthesis of 1-[4-Methyl-2-phenyl-5-(1H-pyrrol-1-yl)thieno[2,3-d]pyrimidin-6-yl]ethanone (4)

A mixture of 1-(5-amino-4-methyl-2-phenylthieno[2,3-d]pyrimidin-6-yl)ethan-one 3 (2.83 g, 0.01 mol), 2,5-dimethoxytetrahydrofuran (1.26 g, 0.01 mol), in glacial acetic acid (20 mL) was refluxed for 12 h. After cooling, the resulting solid product was collected by filtration, washed with water, and the crude product recrystallized from ethanol/glacial acetic acid to give 2.96 g of gray white needles (89% yield), m.p. 204°C; IR: ν 1660 (C=O) cm−1; 1H NMR (CDCl3): δ 2.09 (3H, s, COCH3), 2.20 (3H, s, CH3), 6.50 (2H, t, 3,4-H of pyrrolyl), 6.87 (2H, t, 2,5-H of pyrrolyl), 8.56–8.54, 7.51–7.49 (5H, m, phenyl-H); MS: 333 (M+, 100), 318 (35), 290 (36), 277 (4), 223 (4), 185 (8), 166 (10), 160 (14), 116 (10), 103 (20), 77 (19), 51 (5). Anal. Calcd. for C19H15N3OS: C, 68.46; H, 4.50; N, 12.61. Found: C, 68.33; H, 4.52; N, 12.59%.


## 2.4. Synthesis of 3-Aryl-1-[4-methyl-2-phenyl-5(1H-pyrrol-1-yl)thieno[2,3-d]pyrimidin-6-yl]prop-2-en-1-ones (6a–n) General Procedure

A mixture of compound4 (0.33 g, 1.0 mmol), appropriate aldehydes 5a-n (1.0 mmol) and NaOH (2.2 mmol) in absolute ethanol (10 mL) was stirred at room temperature for 24 h. The mixture was stirred at room temperature for 24 h. The mixture was acidified with dilute acetic acid, and the precipitated product was collected by filtration, washed with water, and the crude product recrystallized from THF/ethanol. The physical constants and spectral data of compounds 6a–n are recorded in Tables 1 and 2.Table 1
Physical and analytical data of 6-(3-substituted-acryloyl)-5-(1-pyrrolyl)-4-methyl-2-phenylthieno[2,3-d]pyrimidine derivatives 6a–n.
Elemental analysis (%)
Dye
M.P.(°C)a
Yield(%)
Molecularformula
Calcd/Found
C
H
N
6a
184
88
C
26
H
18
Cl
N
3
OS
68.49
3.95
9.22
68.55
4.02
9.33
6b
282
96
C
28
H
24
N
4
OS
72.41
5.17
12.06
72.58
5.21
12.12
6c
170
96
C
27
H
21
N
3
OS
74.48
4.82
9.65
74.44
4.92
9.55
6d
262
95
C
27
H
21
N
3
O
2
S
71.84
4.65
9.31
71.80
4.71
9.45
6e
230
93
C
30
H
28
N
4
OS
73.17
5.69
11.38
73.22
5.74
11.24
6f
148
95
C
32
H
23
N
3
OS
77.26
4.62
8.45
77.23
4.77
8.56
6g
130
92
C
24
H
17
N
3
O
2
S
70.07
4.13
10.21
70.15
4.22
10.36
6h
262
98
C
24
H
17
N
3
O
S
2
67.44
3.98
9.83
67.39
4.06
9.89
6i
278
95
C
36
H
23
N
3
OS
79.26
4.22
7.70
79.58
4.56
7.98
6j
178
98
C
34
H
26
N
4
OS
75.83
4.83
10.40
75.88
4.73
10.33
6k
152
93
C
29
H
25
N
3
OS
75.16
5.40
9.07
75.18
5.42
9.24
6l
210
84
C
28
H
22
N
4
O
2
S
70.29
4.60
11.71
70.32
4.56
11.55
6m
228
90
C
34
H
23
N
3
OS
78.31
4.41
8.06
78.29
7.48
7.97
6n
286
94
C
38
H
28
N
4
OS
77.55
4.76
9.52
77.68
4.82
9.52
aRecrystallization from DMF/ethanol.Table 2
Spectra data of 6-(3-substituted-acryloyl)-5-(1-pyrrolyl)-4-methyl-2-phenyl-thieno[2,3-d]pyrimidine derivatives 6a–n.
MS
IR
1H-NMRa
Dye
(m/e M+)
(KBr)
(CF3COOD)
ν (cm−1)
δ (ppm)
6a
455.5
1667 (C=O)
2.20 (3H, s, CH3), 5.80 (1H, d, J=3.1Hz, COCH=), 6.62 (2H, m, 3,4-H of pyrrolyl), 6.87 (2H, m, 2,5-H of pyrrolyl), 6.75 (2H, d, J=1.00Hz, 3,5-H of phenyl), 7.33 (2H, d, J=1.00Hz, 2,6-H of phenyl), 7.82 (1H, d, J=3.1Hz, =CH–), 8.57–8.55, 7.55–7.21 (5H, m, phenyl-H)
6b
464
1628 (C=O)
2.27 (3H, s, CH3), 3.06 (6H, s, N(CH3)2), 5.70 (1H, d, J=3.1Hz, COCH=), 6.59–6.50 (2H, m, 3,4-H of pyrrolyl), 6.98–6.87 (2H, m, 2,5-H of pyrrolyl), 6.70 (2H, d, J=1.0Hz, 3,5-H of phenyl), 7.25 (2H, d, J=1.5Hz, 2,6-H of phenyl), 7.75 (1H, d, J=3.1Hz, =CH–), 8.57–8.54, 7.51–7.50 (5H, m, phenyl-H).
6c
435
1663 (C=O)
2.27 (3H, s, CH3), 2.39 (3H, s, CH3), 6.02 (1H, d, J=3.0Hz, COCH=), 6.61–6.51 (2H, m, 3,4-H of pyrrolyl), 7.09–6.87 (2H, m, 2,5-H of pyrrolyl), 7.79 (1H, d, J=3.0Hz, =CH–), 8.59–8.58, 7.81–7.33 (9H, m, phenyl-H).
6d
451
1668 (C=O)
2.33 (3H, s, CH3), 3.84 (3H, s, OCH3), 5.75 (1H, d, J=3.1Hz, COCH=), 6.60 (2H, t, 3,4-H of pyrrolyl), 6.87 (2H, d, J=1.0Hz, 3,5-H of phenyl), 6.99 (2H, t, 2,5-H of pyrrolyl), 7.28 (2H, d, J=1.0Hz, 2,6-H of phenyl), 7.76 (1H, d, J=3.0Hz, =CH–), 8.59–8.55, 7.52–7.51 (5H, m, phenyl-H).
6e
492
1628 (C=O)
1.21 (6H, t,J=1.4Hz, CH3), 2.27 (3H, s, CH3), 3.41 (4H, q, J=1.4Hz, CH2), 5.68 (1H, d, J=3.1Hz, COCH=), 6.59–6.49 (4H, m, 3,4-H of pyrrolyl and 3,5-H of phenyl), 6.98–6.87 (2H, m, 2,5-H of pyrrolyl), 7.24 (2H, d, J=1.0Hz, 2,6-H of phenyl), 7.74 (1H, d, J=3.0Hz, =CH–), 8.56–8.53, 7.50–7.49 (5H, m, phenyl-H).
6f
497
1667 (C=O)
2.18 (3H, s, CH3), 5.75 (1H, d, J=3.0Hz, COCH=), 6.50 (2H, t, 3,4-H of pyrrolyl), 6.86 (2H, t, 2,5-H of pyrrolyl), 8.65–8.54, 7.63–7.38 (15H, m, =CH– and phenyl-H).
6g
411
1667 (C=O)
2.28 (3H, s, CH3), 5.88 (1H, d, J=3.1Hz, COCH=), 6.59–6.48 (3H, m, 3,4-H of pyrrolyl and 4-H of furyl), 6.87 (2H, m, 2,5-H of pyrrolyl), 7.00 (1H, d, J=2.0Hz, 3-H of furyl), 8.15 (1H, d, J=3.0Hz, =CH–), 8.63–8.54, 7.58–7.48 (6H, m, 5-H of furyl and phenyl-H).
6h
427
1641 (C=O)
2.11 (3H, s, CH3), 5.47 (1H, d, J=3.2Hz, COCH=), 6.63–6.39 (3H, m, 3,4-H of pyrrolyl and 4-H of thienyl), 7.06–7.03 (2H, m, 2,5-H of pyrrolyl), 7.13 (1H, d, J=1.0Hz, 3-H of thienyl), 7.80 (1H, d, J=3.0Hz, =CH–), 8.48–8.45, 7.54–7.44 (6H, m, 5-H of thienyl and phenyl-H).
6i
545
1623 (C=O)
2.06 (3H, s, CH3), 5.79 (1H, d, J=3.1Hz, COCH=), 6.51 (2H, m, 3,4-H of pyrrolyl), 6.90 (2H, m, 2,5-H of pyrrolyl), 8.62–8.42, 8.32–8.05 (15H, m, =CH–, phenyl-H and pyrenyl-H).
6j
538
1633 (C=O)
1.77 (3H, t,J=1.2Hz, CH3), 2.52 (3H, s, CH3), 4.03 (2H, d, J=1.0Hz, CH2), 5.79 (1H, d, J=3.0Hz, COCH=), 6.51 (2H, m, 3,4-H of pyrrolyl), 6.90 (2H, m, 2,5-H of pyrrolyl), 8.72–7.61, (13H, m, =CH–, phenyl-H and carbazolyl-H).
6k
463
1643 (C=O)
2.10 (3H, s, CH3), 2.22 (6H, s, CH3), 2.28 (3H, s, CH3), 5.88 (1H, d, J=4.0Hz, COCH=), 6.51–6.45 (2H, m, 3,4-H of pyrrolyl), 6.88–6.84 (2H, m, 2,5-H of pyrrolyl), 7.39 (1H, d, J=1.2Hz, =CH–), 8.58–8.53, 7.54–7.51 (7H, m, phenyl-H).
6l
478
3324 (NH),1622 (C=O)
2.06 (3H, s, CH3), 2.16 (3H, s, COCH3), 5.78 (1H, d, J=3.0Hz, COCH=), 6.49 (2H, m, 3,4-H of pyrrolyl), 6.97 (2H, m, 2,5-H of pyrrolyl), 6.87 (2H, d, J=1.00Hz, 3,5-H of phenyl), 7.57 (1H, d, J=1.5Hz, =CH–), 8.50–8.29, 7.47–7.41 (7H, m, phenyl-H), 8.29 (1H, br, NH).
6m
521
1679 (C=O)
2.22 (3H, s, CH3), 6.13 (1H, d, J=3.0Hz, COCH=), 6.24 (2H, m, 3,4-H of pyrrolyl), 6.91 (2H, m, 2,5-H of pyrrolyl), 8.93–7.99, 7.54–7.26 (15H, m, =CH–, phenyl-H and anthracenyl-H).
6n
588
1631 (C=O)
2.30 (3H, s, CH3), 5.71 (1H, d, J=3.0Hz, COCH=), 6.55 (2H, t, 3,4-H of pyrrolyl), 6.98–6.94 (4H, m, 3,5-H of phenyl and 2,5-H of pyrrolyl), 7.74 (1H, d, J=3.0Hz, =CH–), 8.59–8.57, 7.53–7.13 (17H, m, phenyl-H).
as: Singlet; d: doublet; t: triplet; m: multiplet; br: broad.


## 2.5. Dyeing Procedure [40]

Polyester fabrics were dyed in a laboratory dyeing machine at a liquor ratio of 30 : 1. Dyebath (60 mL) was prepared with formulated dye and a dispersing agent (Diwatex 40, 0.5 g L−1) and adjusted to pH 4.0. The polyester fabric (2.0 g) was immersed in the dyebath and dyed for 60 min at 130°C. After dyeing, the dyed fabric was reduction cleared (Na2S2O4 2.0 g L−1, NaOH 2.0 g L−1, soaping agent 2.0 g L−1) for 20 min at 75°C.


## 2.6. Fastness Test

The light fastness was determined using standard procedures [41]. For sublimation fastness determinations, the dyed polyester fibers were stitched between two pieces of undyed polyester fibers (stain cloth) and treated at 200°C for 1 min. Any staining on the undyed piece, change in tone, or loss in depth was assessed on 1 (poor) to 5 (very good) rating.


## 2.7. Colorimetric Analysis

The color parameters of the dyed polyester fabrics were measured using the Applied Color System, CS-5 chroma-sensor, model 502 using D65 source and ultraviolet radiation [42]. Each fabric sample was folded twice so as to realize a total of four thicknesses of fabric. The assessment of color-dyed fabrics was made in terms of tristimulus colorimetry [43]. The CIE attributes of lightness (L*), chroma (C*), and hue (a* value represents the degree of redness (positive) and greenness (negative) and b* represents the degree of yellowness (positive) and blueness (negative)) were calculated in the present work.


## 3. Results and Discussion

### 3.1. Synthesis and Spectral Characteristics

All relevant reactions are depicted in Schemes1 and 2. 4-Methyl-2-phenyl-6-thioxo-1,6-dihydropyrimidine-5-carbonitrile 1, which is required as a starting material, was prepared in our previously reported [44]. Cyclization of thioxopyrimidine 1 with chloroacetone 2 in DMF in the presence of excess anhydrous potassium carbonate at room temperature gave the 1-(5-amino- 4-methyl-2-phenylthieno[2,3-d]pyrimidin-6-yl)ethanone 3 in good yields (Scheme 1). The possible mechanism for formation of compound 3 can be explained by the reaction pathway depicted in Scheme 1. The IR spectrum of the compound 3 indicated the absence of the C≡N and C=S groups, and the amino group appears at 3424–3259 cm−1 in the form of two bands due to intramolecular association between the 5-NH2 and 6-COCH3 groups of compound 3 and the characteristic absorption band at 1663 cm−1 for the carbonyl group (C=O). In addition, the 1H NMR spectra (CDCl3) of compound 3 showing a singlet at δ 2.47 (3H, s) assigned for the acetyl group, a broad singlet at 3.76 (2H, br) assigned to the NH2 protons, and a multiplet at δ 8.58–7.55 (5H, m) assigned to the phenyl protons were also confirmed by the mass spectra m/z 283 (M+, 100).Scheme 1
Synthesis of compound4.Scheme 2
Synthesis of chalcone dyes6(a–n).Moreover, treatment of compound3 with 2,5-dimethoxytetrahydrofuran in glacial acetic acid produced the 1-[4-methyl-2-phenyl-5-(1H-pyrrol-1-yl)thieno[2,3-d]-pyrimidin-6-yl]ethanone 4 (Scheme 1). The IR spectrum of the compound 4 indicates the absence of the NH2 group. The 1H NMR spectra (CDCl3) of the compound 4 show a singlet at δ 2.09 (3H, s) assigned for the acetyl group and two triplets at δ 6.50 (2H, t) and 6.87 (2H, t), which were readily assigned to the hydrogen attached at C3, C4 and C2, and C5 of the pyrrolyl ring, respectively. On the other hand, the 3-aryl-1-[4-methyl-2-phenyl-5-(1H-pyrrol-1-yl)thieno[2,3-d]pyrimidin-6-yl]prop-2-en-1-one chalcone dyes 6a–n were obtained in good yields (84–98%) based on Claisen-Schmidt condensation of compound 4 with appropriate aldehydes 5a–n (Scheme 2). The formation of compounds 6a–n can be explained by the reaction pathway depicted in Scheme 2. The mechanism [44] involves base (OH−) removes a C–H proton of CH3CO group in compound 4 to give carbanion 4′, which then adds to C=O group in aldehydes 5, followed then undergoes condensation via dehydration affording the final products 6a–n. The structures of dyes 6a–n were established by examining spectral data and elemental analysis. The IR spectrum of dyes 6a–n indicates the characteristic absorption bands at 1679–1622 cm−1 for the C=O group. Physical and spectral data of dyes 6a–n are given in Tables 1 and 2.


### 3.2. Absorption Spectral Characteristics

The absorption maxima (λmax) of the dyes 6a–n were measured in DMF solution and are listed in Table 3. The absorption maxima of the dyes 6a–n ranged from 412 to 488 nm, with dye 6e showing the highest λmax (488 nm) and 6a the lowest (412 nm). Color shifts are in accord with variations resultant from changes in substituents in these dyes. As seen from Table 3, structural modification occurs only in one terminal moiety, where a p-chlorophenyl donor 6a was replaced by a dialkyl(aryl)aminophenyl or heteroaryl or polycyclic groups. Such a modification could be expected to result in notable changes in the π-conjugated and red shifts in the absorption spectra. The λmax of dyes 6a–n is related to intramolecular charge transfer (ICT) chromophoric system in which these molecules consist of a typical A-π-D structure, where 6-carbonyl-pyrrolythieno[2,3-d]pyrimidinyl, vinyl, and substituent moieties (R) are employed as acceptor (A), π-conjugated center (π), and donor (D) moieties, respectively. The absorption maxima are mainly dominated by the nature of the excited state π-electron system. As well known, a strong electron donor could help to stabilize the charge-separated excited state of the molecule; the red-shift could be explained by the electron-donating strength of donor group [35, 46].Table 3
Absorption spectra and dyeing properties of 6-(3-substituted-acryloyl)-5-(1-pyrrolyl)-4-methyl-2-phenyl-thieno[2,3-d]pyrimidine derivatives 6a–n.
Dye
R
Colour on dyed   polyester fibers
λ
max
ε
×
10
4
Δ
λ
max
Light fastness
Sublimation fastness
(mol−1 cm−1)
(DMF)(nm)
6a
Light yellow
412
6.02
—
5
3-4
6b
Orange
455
1.83
43
1-2
4
6c
Greenish yellow
423
8.43
11
3-4
3-4
6d
Yellow
424
6.24
12
3-4
3-4
6e
Orange
488
3.81
76
2
3
6f
Yellow
456
9.34
44
3-4
5
6g
Yellow
442
6.64
30
2-3
4
6h
Yellow
424
6.23
12
3
4-5
6i
Yellow
478
3.04
66
3-4
4-5
6j
Light yellow
442
4.39
30
1
5
6k
Greenish yellow
440
8.68
28
2
3-4
6l
Yellow
453
1.13
41
2
4-5
6m
Orange yellow
481
7.17
69
3
5
6n
Orange
470
4.09
58
4-5
4-5Compound6a, as a standard, absorbed at 412 nm and substituent effects on the absorption maxima were evaluated compared with this value. As is apparent in Table 3, introduction of electron-donating substituents into the 6-carbonyl-pyrroly-thieno[2,3-d]pyrimidinyl-based chromophore produces a significant bathochromic shifts of the absorption maxima. The differences of these values are shown by Δλmax. As a result, the dyes 6b–n were bathochromic shift of 11–76 nm. It can be seen from Table 3 that dyes 6b, 6e, 6l, and 6n selected in this case produced bathochromic shifts of 41 to 76 nm caused by introduction of the stronger electron-donating substituents (dialkyl(aryl)aminophenyl) into 6-carbonyl-pyrrolythieno[2,3-d]pyrimidinyl-based chromophore at which there is an electron density decrease that should produce a bathochromic shift of λmax [46]. In general, with respect to the substituents R of dyes 6b, 6e, 6l, and 6n, the dyes were bathochromically shifted in the following order: diethylaminophenyl (6e) (Δλmax 76 nm)>diphenylaminophenyl (6n) (Δλmax 58 nm)>dimethylaminophenyl (6b) (Δλmax 43 nm)>4-acetamidophenyl (6l) (Δλmax 41 nm). Furthermore, the spectroscopic data also demonstrate that the dye 6e (λmax 488 nm) containing the diethylaminophenyl group showed a largest bathochromic shift of 76 nm.On the other hand,λmax value in the case of selected dyes 6c, 6f, 6i, 6j, 6k, and 6m indicates that replacement of the p-chlorophenyl group of dye 6a for appropriate heteroaryl or polycyclic substituents, such as tolyl (6c),biphenylyl (6f), pyrenyl (6i), carbazolyl (6j), 2,4,6-trimethylphenyl (6k), and anthryl (6m), leads to a significant bathochromic shift of 11 to 69 nm. The differences of these values are shown by Δλmax. For instance, dye 6a was absorbed at 412 nm, with increasing donor ability from the p-chlorophenyl (6a) to the carbazolyl (6j), pyrenyl (6i), and anthryl (6m); their Δλmax values show large bathochromic shifts to 442 nm (Δλmax=30 nm), 478 nm (Δλmax=66 nm), and 481 nm (Δλmax=69 nm), respectively. In general, with respect to the substituents R of dyes 6c, 6f, 6i, 6j, 6k, and 6m, the dyes were bathochromically shifted in the following order: anthryl (6m) (Δλmax 69 nm)>pyrenyl (6i) (Δλmax 66 nm)>biphenylyl (6f) (Δλmax 44 nm)>carbazolyl (6j) (Δλmax 30 nm)>2,4,6-trimethylphenyl (6k) (Δλmax 28 nm)>tolyl (6c) (Δλmax 11 nm). Moreover, the spectroscopic data also demonstrate that the dye 6g (λmax 442 nm) containing the furyl moiety shows a bathochromic shift of 18 nm in comparison with the dye 6h (λmax 424 nm) containing the thienyl moiety.In brief, dyes derived from dialkyl(arkyl)aminophenyl substituents exhibited significantly larger bathochromic shift compared with those derived from heteroaryl or polycyclic substituents. Furthermore, it is well known that molar extinction coefficientsε values reflect the molecular planarity and enlargement of π-conjugation. The dyes 6c, 6f, 6k, and 6m have bigger ε values than those of other dyes which indicates that dyes 6c, 6f, 6k, and 6m have much more planar and rigid π-conjugation system than that of other dyes [47].


### 3.3. Dyeing and Fastness Properties

For imparting greenish-yellow to orange hues, the dyes6a–n were applied to polyester fiber at 1% shade by high-temperature-pressure techniques. The fastness properties of the dyes are shown in Table 3. Table 3 shows that the light fastness of these dyes varied from 1–5; thus the dyes 6b, 6e, 6g, 6j, 6k, and 6l had poor light fastness (1-2), dyes 6c, 6d, 6f, 6h, 6i, and 6m had fair light fastness (3-4), and dyes 6a and 6n had good light fastness (4-5). In general, the dyes in the range of 3–5 show good sublimation fastness properties on polyester fibers.


### 3.4. Colorimetric Assessment

Three important attributes of color that must be considered in the development of new colorants are lightness, chroma, and hue. These attributes can be determined by colorimetric assessment using the prototype dye. The CIE attributes of lightness (L*), chroma (C*), and hue (a*= redness/greenness; b* = yellowness/blueness) were calaulated in the present work. The values of the CIE coordinate (L*, a*, b*, h°, and C*) are listed in Table 4. According to Richter [48] and McLaren et al. [49] the position of the color is distributed in the red-green area with hue angle h° 33.07–116.83° and radial chroma C* of length 8.35–48.08. Figure 1 shows a graph of CIE coordinates a* versus b* for selected dyes 6b, 6e, 6l, and 6n (an increasing a* value represents an increase in redness, while a decrease in a* represents a green hue shift). Dyes 6l and 6n provided a reference point for the color attributes of each dye, since 6l is a yellow and 6n is a strong orange. The dye based on dimethylaminophenyl (6b) was yellow-orange, and thus the a*b* graph shows the dye to be bathochromic compared with 6l and hypsochromic relative to 6n. Apart from 6e and 6n, dyes displayed similar hues both to each other and to 6l. Hence, the presence of stronger electron-donating substituents in the 6-carbonyl-pyrrolythieno[2,3-d]pyrimidinyl-based chromophore linkage produced the desired colorimetric effect.Table 4
CIE of dyes6a–n on polyester.
Dye
L
*
a
*
b
*
C
*
h
o
K/S
6a
88.40
0.09
9.52
9.52
90.56
0.1789
6b
91.32
17.34
37.98
41.76
65.46
0.9125
6c
84.29
−3.77
7.45
8.35
116.83
0.3417
6d
91.06
−6.12
21.90
22.74
105.60
0.4236
6e
85.84
33.35
34.63
25.55
46.06
1.3319
6f
89.61
−0.79
15.38
15.40
92.96
0.2368
6g
73.24
6.04
15.97
17.07
69.27
0.7793
6h
88.41
−3.80
24.22
24.52
98.92
0.5565
6i
89.52
−0.10
11.27
11.27
90.50
0.3050
6j
90.60
−6.69
33.96
34.61
101.14
0.8942
6k
82.53
−2.94
12.51
12.85
103.22
0.6437
6l
85.06
5.34
24.99
48.08
46.08
0.4600
6m
83.41
9.27
20.99
22.95
66.18
0.3820
6n
76.37
35.23
22.94
42.04
33.07
0.5334Figure 1
Graph of CIEa* versus b* for selected dyes.Furthermore, Figures2 and 3 show a graph of CIE C* versus L* for selected dyes (6b, 6e, 6l and 6n) and (6a, 6c, 6d, 6f–6k, and 6m), respectively. In general, dyes derived from dialkyl(arkyl)aminophenyl substituents exhibited significantly higher chroma compared with those derived from heteroaryl or polychlic substituents. Figure 2 shows that the dyes 6b, 6e, and 6l were lighter than 6n. Similar results are observed in Figure 3; the lightness of 6a, 6c, 6d, 6f, 6h–k, and 6m were all high except for dye 6g.Figure 2
Graph of CIEC* versus L* for selected dyes.Figure 3
Graph of CIEC* versus L* for selected dyes.On the other hand, Figure4 shows a graph of CIE coordinates a* versus b* for selected dyes 6a, 6c, 6d, 6f–6k and 6m. As the b* scale represents yellowness (increasing b* value) versus blueness (decreasing b* value), it is evident that most of the new dyes were significantly yellower than 6c. The dye 6f based on biphenylyl possessed approximately the same yellowness but was redder than dye 6j. However, the dyes 6c, 6d, 6h, and 6k were green hue shift relative to the dye 6f, although not as green as 6j, and were similar in hue to 6d. Also, the dyes based on p-chlorophenyl (6a) and tolyl (6c) were bluer than biphenylyl (6f) and 2,4,6-trimethylphenyl (6k). In the case of 6a and 6c, the hypsochromic shift due to the presence of weak electron-donating substituents in the 6-carbonyl-pyrrolythieno[2,3-d]pyrimidinyl-based chromophore linkage is significant. In addition, dyes based on furyl (6g) and anthryl (6m) were bathochromic relative to when p-chlorophenyl (6a) was employed.Figure 4
Graph of CIEa* versus b* for selected dyes.


## 3.1. Synthesis and Spectral Characteristics

All relevant reactions are depicted in Schemes1 and 2. 4-Methyl-2-phenyl-6-thioxo-1,6-dihydropyrimidine-5-carbonitrile 1, which is required as a starting material, was prepared in our previously reported [44]. Cyclization of thioxopyrimidine 1 with chloroacetone 2 in DMF in the presence of excess anhydrous potassium carbonate at room temperature gave the 1-(5-amino- 4-methyl-2-phenylthieno[2,3-d]pyrimidin-6-yl)ethanone 3 in good yields (Scheme 1). The possible mechanism for formation of compound 3 can be explained by the reaction pathway depicted in Scheme 1. The IR spectrum of the compound 3 indicated the absence of the C≡N and C=S groups, and the amino group appears at 3424–3259 cm−1 in the form of two bands due to intramolecular association between the 5-NH2 and 6-COCH3 groups of compound 3 and the characteristic absorption band at 1663 cm−1 for the carbonyl group (C=O). In addition, the 1H NMR spectra (CDCl3) of compound 3 showing a singlet at δ 2.47 (3H, s) assigned for the acetyl group, a broad singlet at 3.76 (2H, br) assigned to the NH2 protons, and a multiplet at δ 8.58–7.55 (5H, m) assigned to the phenyl protons were also confirmed by the mass spectra m/z 283 (M+, 100).Scheme 1
Synthesis of compound4.Scheme 2
Synthesis of chalcone dyes6(a–n).Moreover, treatment of compound3 with 2,5-dimethoxytetrahydrofuran in glacial acetic acid produced the 1-[4-methyl-2-phenyl-5-(1H-pyrrol-1-yl)thieno[2,3-d]-pyrimidin-6-yl]ethanone 4 (Scheme 1). The IR spectrum of the compound 4 indicates the absence of the NH2 group. The 1H NMR spectra (CDCl3) of the compound 4 show a singlet at δ 2.09 (3H, s) assigned for the acetyl group and two triplets at δ 6.50 (2H, t) and 6.87 (2H, t), which were readily assigned to the hydrogen attached at C3, C4 and C2, and C5 of the pyrrolyl ring, respectively. On the other hand, the 3-aryl-1-[4-methyl-2-phenyl-5-(1H-pyrrol-1-yl)thieno[2,3-d]pyrimidin-6-yl]prop-2-en-1-one chalcone dyes 6a–n were obtained in good yields (84–98%) based on Claisen-Schmidt condensation of compound 4 with appropriate aldehydes 5a–n (Scheme 2). The formation of compounds 6a–n can be explained by the reaction pathway depicted in Scheme 2. The mechanism [44] involves base (OH−) removes a C–H proton of CH3CO group in compound 4 to give carbanion 4′, which then adds to C=O group in aldehydes 5, followed then undergoes condensation via dehydration affording the final products 6a–n. The structures of dyes 6a–n were established by examining spectral data and elemental analysis. The IR spectrum of dyes 6a–n indicates the characteristic absorption bands at 1679–1622 cm−1 for the C=O group. Physical and spectral data of dyes 6a–n are given in Tables 1 and 2.


## 3.2. Absorption Spectral Characteristics

The absorption maxima (λmax) of the dyes 6a–n were measured in DMF solution and are listed in Table 3. The absorption maxima of the dyes 6a–n ranged from 412 to 488 nm, with dye 6e showing the highest λmax (488 nm) and 6a the lowest (412 nm). Color shifts are in accord with variations resultant from changes in substituents in these dyes. As seen from Table 3, structural modification occurs only in one terminal moiety, where a p-chlorophenyl donor 6a was replaced by a dialkyl(aryl)aminophenyl or heteroaryl or polycyclic groups. Such a modification could be expected to result in notable changes in the π-conjugated and red shifts in the absorption spectra. The λmax of dyes 6a–n is related to intramolecular charge transfer (ICT) chromophoric system in which these molecules consist of a typical A-π-D structure, where 6-carbonyl-pyrrolythieno[2,3-d]pyrimidinyl, vinyl, and substituent moieties (R) are employed as acceptor (A), π-conjugated center (π), and donor (D) moieties, respectively. The absorption maxima are mainly dominated by the nature of the excited state π-electron system. As well known, a strong electron donor could help to stabilize the charge-separated excited state of the molecule; the red-shift could be explained by the electron-donating strength of donor group [35, 46].Table 3
Absorption spectra and dyeing properties of 6-(3-substituted-acryloyl)-5-(1-pyrrolyl)-4-methyl-2-phenyl-thieno[2,3-d]pyrimidine derivatives 6a–n.
Dye
R
Colour on dyed   polyester fibers
λ
max
ε
×
10
4
Δ
λ
max
Light fastness
Sublimation fastness
(mol−1 cm−1)
(DMF)(nm)
6a
Light yellow
412
6.02
—
5
3-4
6b
Orange
455
1.83
43
1-2
4
6c
Greenish yellow
423
8.43
11
3-4
3-4
6d
Yellow
424
6.24
12
3-4
3-4
6e
Orange
488
3.81
76
2
3
6f
Yellow
456
9.34
44
3-4
5
6g
Yellow
442
6.64
30
2-3
4
6h
Yellow
424
6.23
12
3
4-5
6i
Yellow
478
3.04
66
3-4
4-5
6j
Light yellow
442
4.39
30
1
5
6k
Greenish yellow
440
8.68
28
2
3-4
6l
Yellow
453
1.13
41
2
4-5
6m
Orange yellow
481
7.17
69
3
5
6n
Orange
470
4.09
58
4-5
4-5Compound6a, as a standard, absorbed at 412 nm and substituent effects on the absorption maxima were evaluated compared with this value. As is apparent in Table 3, introduction of electron-donating substituents into the 6-carbonyl-pyrroly-thieno[2,3-d]pyrimidinyl-based chromophore produces a significant bathochromic shifts of the absorption maxima. The differences of these values are shown by Δλmax. As a result, the dyes 6b–n were bathochromic shift of 11–76 nm. It can be seen from Table 3 that dyes 6b, 6e, 6l, and 6n selected in this case produced bathochromic shifts of 41 to 76 nm caused by introduction of the stronger electron-donating substituents (dialkyl(aryl)aminophenyl) into 6-carbonyl-pyrrolythieno[2,3-d]pyrimidinyl-based chromophore at which there is an electron density decrease that should produce a bathochromic shift of λmax [46]. In general, with respect to the substituents R of dyes 6b, 6e, 6l, and 6n, the dyes were bathochromically shifted in the following order: diethylaminophenyl (6e) (Δλmax 76 nm)>diphenylaminophenyl (6n) (Δλmax 58 nm)>dimethylaminophenyl (6b) (Δλmax 43 nm)>4-acetamidophenyl (6l) (Δλmax 41 nm). Furthermore, the spectroscopic data also demonstrate that the dye 6e (λmax 488 nm) containing the diethylaminophenyl group showed a largest bathochromic shift of 76 nm.On the other hand,λmax value in the case of selected dyes 6c, 6f, 6i, 6j, 6k, and 6m indicates that replacement of the p-chlorophenyl group of dye 6a for appropriate heteroaryl or polycyclic substituents, such as tolyl (6c),biphenylyl (6f), pyrenyl (6i), carbazolyl (6j), 2,4,6-trimethylphenyl (6k), and anthryl (6m), leads to a significant bathochromic shift of 11 to 69 nm. The differences of these values are shown by Δλmax. For instance, dye 6a was absorbed at 412 nm, with increasing donor ability from the p-chlorophenyl (6a) to the carbazolyl (6j), pyrenyl (6i), and anthryl (6m); their Δλmax values show large bathochromic shifts to 442 nm (Δλmax=30 nm), 478 nm (Δλmax=66 nm), and 481 nm (Δλmax=69 nm), respectively. In general, with respect to the substituents R of dyes 6c, 6f, 6i, 6j, 6k, and 6m, the dyes were bathochromically shifted in the following order: anthryl (6m) (Δλmax 69 nm)>pyrenyl (6i) (Δλmax 66 nm)>biphenylyl (6f) (Δλmax 44 nm)>carbazolyl (6j) (Δλmax 30 nm)>2,4,6-trimethylphenyl (6k) (Δλmax 28 nm)>tolyl (6c) (Δλmax 11 nm). Moreover, the spectroscopic data also demonstrate that the dye 6g (λmax 442 nm) containing the furyl moiety shows a bathochromic shift of 18 nm in comparison with the dye 6h (λmax 424 nm) containing the thienyl moiety.In brief, dyes derived from dialkyl(arkyl)aminophenyl substituents exhibited significantly larger bathochromic shift compared with those derived from heteroaryl or polycyclic substituents. Furthermore, it is well known that molar extinction coefficientsε values reflect the molecular planarity and enlargement of π-conjugation. The dyes 6c, 6f, 6k, and 6m have bigger ε values than those of other dyes which indicates that dyes 6c, 6f, 6k, and 6m have much more planar and rigid π-conjugation system than that of other dyes [47].


## 3.3. Dyeing and Fastness Properties

For imparting greenish-yellow to orange hues, the dyes6a–n were applied to polyester fiber at 1% shade by high-temperature-pressure techniques. The fastness properties of the dyes are shown in Table 3. Table 3 shows that the light fastness of these dyes varied from 1–5; thus the dyes 6b, 6e, 6g, 6j, 6k, and 6l had poor light fastness (1-2), dyes 6c, 6d, 6f, 6h, 6i, and 6m had fair light fastness (3-4), and dyes 6a and 6n had good light fastness (4-5). In general, the dyes in the range of 3–5 show good sublimation fastness properties on polyester fibers.


## 3.4. Colorimetric Assessment

Three important attributes of color that must be considered in the development of new colorants are lightness, chroma, and hue. These attributes can be determined by colorimetric assessment using the prototype dye. The CIE attributes of lightness (L*), chroma (C*), and hue (a*= redness/greenness; b* = yellowness/blueness) were calaulated in the present work. The values of the CIE coordinate (L*, a*, b*, h°, and C*) are listed in Table 4. According to Richter [48] and McLaren et al. [49] the position of the color is distributed in the red-green area with hue angle h° 33.07–116.83° and radial chroma C* of length 8.35–48.08. Figure 1 shows a graph of CIE coordinates a* versus b* for selected dyes 6b, 6e, 6l, and 6n (an increasing a* value represents an increase in redness, while a decrease in a* represents a green hue shift). Dyes 6l and 6n provided a reference point for the color attributes of each dye, since 6l is a yellow and 6n is a strong orange. The dye based on dimethylaminophenyl (6b) was yellow-orange, and thus the a*b* graph shows the dye to be bathochromic compared with 6l and hypsochromic relative to 6n. Apart from 6e and 6n, dyes displayed similar hues both to each other and to 6l. Hence, the presence of stronger electron-donating substituents in the 6-carbonyl-pyrrolythieno[2,3-d]pyrimidinyl-based chromophore linkage produced the desired colorimetric effect.Table 4
CIE of dyes6a–n on polyester.
Dye
L
*
a
*
b
*
C
*
h
o
K/S
6a
88.40
0.09
9.52
9.52
90.56
0.1789
6b
91.32
17.34
37.98
41.76
65.46
0.9125
6c
84.29
−3.77
7.45
8.35
116.83
0.3417
6d
91.06
−6.12
21.90
22.74
105.60
0.4236
6e
85.84
33.35
34.63
25.55
46.06
1.3319
6f
89.61
−0.79
15.38
15.40
92.96
0.2368
6g
73.24
6.04
15.97
17.07
69.27
0.7793
6h
88.41
−3.80
24.22
24.52
98.92
0.5565
6i
89.52
−0.10
11.27
11.27
90.50
0.3050
6j
90.60
−6.69
33.96
34.61
101.14
0.8942
6k
82.53
−2.94
12.51
12.85
103.22
0.6437
6l
85.06
5.34
24.99
48.08
46.08
0.4600
6m
83.41
9.27
20.99
22.95
66.18
0.3820
6n
76.37
35.23
22.94
42.04
33.07
0.5334Figure 1
Graph of CIEa* versus b* for selected dyes.Furthermore, Figures2 and 3 show a graph of CIE C* versus L* for selected dyes (6b, 6e, 6l and 6n) and (6a, 6c, 6d, 6f–6k, and 6m), respectively. In general, dyes derived from dialkyl(arkyl)aminophenyl substituents exhibited significantly higher chroma compared with those derived from heteroaryl or polychlic substituents. Figure 2 shows that the dyes 6b, 6e, and 6l were lighter than 6n. Similar results are observed in Figure 3; the lightness of 6a, 6c, 6d, 6f, 6h–k, and 6m were all high except for dye 6g.Figure 2
Graph of CIEC* versus L* for selected dyes.Figure 3
Graph of CIEC* versus L* for selected dyes.On the other hand, Figure4 shows a graph of CIE coordinates a* versus b* for selected dyes 6a, 6c, 6d, 6f–6k and 6m. As the b* scale represents yellowness (increasing b* value) versus blueness (decreasing b* value), it is evident that most of the new dyes were significantly yellower than 6c. The dye 6f based on biphenylyl possessed approximately the same yellowness but was redder than dye 6j. However, the dyes 6c, 6d, 6h, and 6k were green hue shift relative to the dye 6f, although not as green as 6j, and were similar in hue to 6d. Also, the dyes based on p-chlorophenyl (6a) and tolyl (6c) were bluer than biphenylyl (6f) and 2,4,6-trimethylphenyl (6k). In the case of 6a and 6c, the hypsochromic shift due to the presence of weak electron-donating substituents in the 6-carbonyl-pyrrolythieno[2,3-d]pyrimidinyl-based chromophore linkage is significant. In addition, dyes based on furyl (6g) and anthryl (6m) were bathochromic relative to when p-chlorophenyl (6a) was employed.Figure 4
Graph of CIEa* versus b* for selected dyes.


## 4. Conclusions

Fourteen novel heterocyclic chalcone derivatives containing a thieno-[2,3-d]pyrimidine-based chromophore were obtained from thioxopyrimidine 1. The chalcone derivatives were applied to polyester fibers as disperse dyes for creating hues ranging from greenish-yellow to orange. The substituent effect in DMF solution was also discussed. The results indicate that the novel chalcone dyes derived from dialkyl(arkyl)aminophenyl substituents exhibited significantly larger bathochromic shift compared with those derived from heteroaryl or polycyclic substituents. On the other hand, color shifts are in accord with variations resultant from changes in substituents in these dyes. In general, the presence of dialkyl(aryl)aminophenyl substituents in the thieno[2,3-d]pyrimidinyl-based chromophore linkage produced the red hue shift, while the heteroaryl or polychlic substituents produced the green hue shift. In addition, these dyes showed good sublimation fastness and poor- to good-light fastness on polyester fibers.



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*Source: 649576-2013-01-03.xml*