# Synthesis and Evaluation of Novel Pyrroles and Pyrrolopyrimidines as Anti-Hyperglycemic Agents

Authors: M. S. Mohamed; S. A. Ali; D. H. A. Abdelaziz; Samar S. Fathallah
Journal: BioMed Research International
 (2014)

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## Abstract

A series of pyrrole and pyrrolopyrimidine derivatives were examined for theirin vivo antihyperglycemic activity. Compounds Ia–c,e, and IVg showed promising antihyperglycemic activity equivalent to a well-known standard antihyperglycemic drug, Glimepiride (Amaryl, 4 mg/kg). In this paper, we examine and discuss the structure-activity relationships and antihyperglycemic activity of these compounds.


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## Body

## 1. Introduction

For several decades, interest in pyrrole derivatives increases due to their pharmaceutical importance [1–3], such as antimicrobial [4–8], antiviral [9, 10], anti-inflammatory [11–13], analgesic [14], antitumor [15, 16], antihyperlipidemic [17], anticonvulsant [18], and antihyperglycemic agents [19, 20], as shown in Figures 1 and 2(a).Pyrrole as valuable leads in the drug discovery field.
(a)
(b)(a) Pyrroles as antihyperglycemic agents [19, 20], (b) Amaryl, standard antihyperglycemic drug [21, 22], and approved DPP-IV inhibitors [23–25] as type 2 diabetes medications containing a pyrrole moiety. (c) Thieno and Pyrrolo-pyrimidines as DPP-IV inhibitors.
(a)
(b)
(c)Likewise, the key roles played by purines and pyrimidines in cellular processes have made them valuable lead for drug discovery; among these, pyrrolo[3,2-d]pyrimidines, a class of 7-deazapurine analogs, exhibit interesting biological activity in part due to their resemblance to pyrimidines and purines. These huge therapeutic applications have motivated new efforts in the search for novel derivatives with improved biological activity and diverse applications in the pharmaceutical industry [1–4, 19, 20].Diabetes mellitus (DM) is a severe metabolic disorder that has a significant impact on the health and quality of patients’ life. Treatment of diabetic patients has been focused on dietary management and oral antidiabetics, among these: sulfonylureas, metformin, acarbose, and others. However, some of the currently used antihyperglycemic have several adverse side effects like hepatotoxicity, weight gain, and hypoglycemia.This situation emphasized the need to develop novel antihyperglycemic agents [21]. Glimepiride (Amaryl) is a sulfonylurea containing a pyrrole group, acting as antihyperglycemic drug [22]. It is sometimes classified either as the first third-generation sulfonylurea or as second-generation. Glimepiride is indicated to treat type 2 diabetes mellitus; its mode of action is to increase insulin production by the pancreas, as shown in Figure 2(b).Recently, dipeptidyl peptidase IV (DPP-IV) inhibitors [23–25] have been shown to be effective and safe compounds that control blood glucose. Improvement of the inhibitory activity and chemical stability of a series of substituted piperidinyl glycine 2-cyano-4,5-methano pyrroline (DPP-IV) inhibitors was, respectively, achieved by the introduction of pyrroline moiety at the 4 position and 1 position of the piperidinyl glycine, leading to a series of potent and stable DPP-IV inhibitors [25]. Two important DPP-IV inhibitors, having a pyrrole and fused pyrrole, vildaglipin, and saxagliptin [24, 25], are on the market in many countries, as shown in Figure 2(b).A highly potent DPP-IV inhibitor thienopyrimidine was also reported [24]. While trying to maintain consistency ofin vitro andin vivo biological activity, a simple scaffold replacement of thienopyrimidine with pyrrolopyrimidine lead to significantly improved metabolic stability [22–24], as shown in Figure 2(c).Motivated by the importance of this system and in continuation of our research efforts [26–30], we try to highlight aspects reported on the chemistry of some newly synthesized pyrrole and pyrrolopyrimidine derivatives and evaluate them for the antihyperglycemic activities. The synthetic pathways adopted for the synthesis of these compounds are registered in Schemes 1–3.Scheme 1
Synthetic pathways for compoundsIa–o: reagents and conditions: (1) pyridine/benzene; (2) CH2(CN)2; (3) NaHCO3/EtOH; (4) CH2(CN)2/NaOEt; (5) TEOF; or (6) Ac2O.


## 2. Materials and Methods

### 2.1. Chemistry

All melting points were uncorrected and measured using Electrothermal IA 9100 apparatus (Shimadzu, Japan). IR spectra were recorded as potassium bromide pellets on a Perkin-Elmer 1650 spectrophotometer (USA), Faculty of Science, Cairo University, Cairo, Egypt.1H NMR and 13CNMR spectra were performed on JOEL NMR FXQ-300 MHz and JOELNMR FXQ-500 MHz spand chemical shifts were expressed as ppm against TMS as internal reference (Faculty of Science, Cairo University, Cairo, Egypt). Mass spectra were recorded at 70 eV EI Ms-QP 1000 EX (Shimadzu, Japan), Faculty of Science, Cairo University, Cairo, Egypt. Microanalyses were operated using Vario, Elementar apparatus (Shimadzu, Japan), Organic Microanalysis Unit, Faculty of Science, Cairo University, Cairo, Egypt. Column chromatography was performed on (Merck) silica gel 60 (particle size 0.06–0.20 mm). CompoundsIa–c,f–h,k–m,IIa–c,f–h,IIIa–c,f–h,IVa–c,Va–c,VIa–c,VIIa–c,andVIIIa–c were prepared as reported in the literature [26–31]. All new compounds yielded spectral data consistent with the proposed structure and microanalysis within ± 0.4% of the theoretical values.


#### 2.1.1. 2-Amino-1-(3,4-dichlorophenyl)-4,5-diphenyl-1H-pyrrole-3-carbonitrileId (Scheme 1)

A mixture of benzoin (2 g, 0.01 mol), 3,4-dichlorophenyl amine (1.6 g, 0.01 mol) in dry benzene (50 mL), was kept at 80°C for 9 h. The reaction mixture was cooled; then malononitrile (0.66 mg, 0.01 mol) was added, followed by catalytic amount of pyridine (2 mL) portion wise and left to reflex till solid formed. The solvent was evaporated under reduced pressure and the residue was recrystallized from methanol to giveId. Yield: 45%; M.P. 118–122°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 5.21 (br.s, 2H, NH2, D2O exchangeable), 7.0–7.8 (m, 13H, Ar-H); 13C NMR (DMSO-d
6): δ 114.33, 118.24, 119.37, 125.8, 126.18, 127.80, 128.45, 129.84, 130.29, 132.16, 132.70, 133.62, 134.96, 142.05 ppm; IR (KBr) υ (cm−1): 3410, 3370 (NH2), 2220 (C≡N); MS (EI)m/z: 403 (M+, 14%), 405 (M++ 2, 8.75%), 407 (M++ 4, 1.1%); Anal. Calcd for C23H15Cl2N3 (403.06): C, 68.33; H, 3.74; Cl, 17.54; N, 10.39%. Found: C, 68.55; H, 3.92; Cl, 17.23; N, 10.72%.


#### 2.1.2. 2-Amino-1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H -pyrazol-4-yl)-4-phenyl-1H -pyrrole-3-carbonitrileIe (Scheme 1)

1,5-Dimethyl-4-(2-oxo-2-phenylethylamino)-2-phenyl-1H-pyrazol-3(2H)-one [27–30](3.22 g, 0.01 mol) was dissolved in dry ethanol (20 mL); then malononitrile (0.66 g, 0.01 mol) was added, followed by sodium ethoxide (0.01 mol) portion wise, and left to reflux till solid formed. The solvent was evaporated under reduced pressure and the residue was recrystallized from methanol to giveIe.Yield: 66%; M.P. 163–166°C;1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.43 (s, 3H, CH3), 3.12 (s, 3H, N-CH3), 6.13 (br.s, 2H, NH2, D2O exchangeable), 6.8–7.8 (m, 10H, Ar-H and 1H, C6-H); IR (KBr) υ (cm−1): 3410, 3350 (NH2), 2210 (C≡N), 1703 (C=O); MS (EI)m/z: 369 (M+, 23%), 370 (M++ 1, 6.1%); Anal. Calcd for C22H19N5O (369.16): C, 71.53; H, 5.18; N, 18.96; O, 4.33%. Found: C, 71.55; H, 5.26; N, 18.70; O, 3.05%.


#### 2.1.3. 2-Ethoxymethylenamino-1,5-disubstituted-4-phenyl-1H -pyrrole-3-carbonitrilesIi,j (Scheme 1)

CompoundI,d,or e (0.01 mol) in triethyl orthoformate (20 mL) was refluxed for 9 h. The solvent was removed under reduced pressure and the residue was recrystallized from methanol/water to give the target compoundsIi,j.


#### 2.1.4. Ethyl N-3-Cyano-1-(3,4-dichlorophenyl)-4,5-diphenyl-1H -pyrrol-2-ylformimidateIi

Yield: 60%; M.P. 120–122°C;1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 1.30 (t, 3H,J = 7.1 Hz, CH3), 4.2 (q, 2H,J= 7.1 Hz, OCH2), 6.9–7.8 (m, 14H, Ar-H and N=CH); IR (KBr) υ (cm−1): 3070, 2900(CH), 2310(CN), 1620 (C=C), 1560 (C=N); MS (EI)m/z: 460 (M+, 13.5%), 462 (M++ 2, 8.5%), 464 (M++ 4, 2.71%); Anal. Calcd for C26H19Cl2N3O (460.35): C, 67.83; H, 4.16; Cl, 15.40; N, 9.13; O, 3.48%, Found: C, 68.03; H, 4.11; Cl, 15.63; N, 8.91; O, 3.69%.


#### 2.1.5. Ethyl N-3-Cyano-1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H -pyrazol-4-yl)-4-phenyl-1H -pyrrol-2-ylacetimidateIj

Yield: 56%; M.P. 120–122°C;1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 1.20 (t, 3H,J = 7.2 Hz, CH3), 2.41 (s, 3H, CH3), 3.1 (s, 3H, N-CH3), 4.01 (q, 2H,J= 7.1 Hz, OCH2), 6.9–7.8 (m, 12H, Ar-H, C6-H and N=CH); IR (KBr) υ (cm−1): 3030, 2910(CH), 2240(CN), 1610 (C=C), 1570 (C=N); MS (EI)m/z: 425 (M+, 6.5%), 426 (M++ 1, 1.81%); Anal. Calcd for C26H23N5O2 (425.19): C, 70.57; H, 5.45; N, 16.46; O, 7.52%. Found: C, 70.21; H, 5.17; N, 16.12; O, 7.18%.


#### 2.1.6. N-(4-Phenyl-1,3,5-trisubstituted-1H -pyrrol-2-yl)-acetamidesI n,o (Scheme 1)

CompoundI,d, ore (0.01 mol) in acetic anhydride (30 mL) was refluxed for 2 h, cooled, poured onto ice water, neutralized with ammonia to give a precipitate which was filtered off, dried, and recrystallized from methanol to give the target compoundsIn,o.


#### 2.1.7. N-(3-Cyano-1-(3,4-dichlorophenyl)-4,5-diphenyl-1H -pyrrol-2-yl) acetamideIn

Yield: 66%; M.P. 135–138°C;1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.23 (s, 3H, CO-CH3), 7.0–7.8 (m, 13H, Ar-H), 9.5 (s, 1H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3430 (NH), 2330 (C≡N), 1710 (C=O); MS (EI)m/z: 445 (M+, 13.1%), 447 (M+ + 2, 7.9%), 449 (M+ + 4, 0.91%); Anal. Calcd for C25H17Cl2N3O (445.07): C, 67.28; H, 3.84; Cl, 15.89; N, 9.41; O, 3.58%. Found: C, 67.47; H, 4.06; Cl, 16.22; N, 9.57; O, 3.66%.


#### 2.1.8. N-(3-Cyano-1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H -pyrazol-4-yl)-4-phenyl-1H -pyrrol-2-yl)acetamideIo

Yield: 72%; M.P. 135–138°C;1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.23 (s, 3H, CO-CH3), 2.43 (s, 3H, CH3), 3.12 (s, 3H, N-CH3), 7.0–7.8 (m, 11H, Ar-H and C6-H), 9.4 (s, 1H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3350 (NH), 2310 (C≡N), 1715, 1705 (C=O); MS (EI)m/z: 411 (M+, 15.4%), 412 (M++ 1, 3.73%); Anal. Calcd for C24H21N5O2 (411.17): C, 70.06; H, 5.14; N, 17.02; O, 7.78%. Found: C, 70.37; H, 5.45; N, 17.34; O, 7.95%.


#### 2.1.9. 7-(2,4-Dimethyl-5-oxo-1-phenyl-2,5-dihydro-1H -pyrazol-3-yl)-5,6-diphenyl -3H-pyrrolo[2,3-d]pyrimidin-4(7H)-oneIId,e (Scheme 2)

Scheme 2
Synthetic pathways for compoundsI–VI: reagents and conditions: (1) HCO2H; (2) AcOH/HCl; (3) HCONH2; (4) NH2CSNH2; (5) POCl3; (6) N2H4·H2O; and (7) NH2CSNH2.Scheme 3
Synthetic pathways for compoundsVII–VIII: reagents and conditions: (1) NaNO2/HCl/Stirring (75 min); (2) NCCH2Y/CH3CO2NH4/EtOH; and (3) N2H4
·H2O.CompoundId ore (0.01 mol) in formic acid (20 mL, 85%) was refluxed for 12 h. The reaction mixture was cooled, poured onto ice/water to give a precipitate which was filtered, dried, and recrystallized from ethanol to give the target compoundsIId,e.7-(3,4-Dichlorophenyl)-5,6-diphenyl-3H-pyrrolo[2,3-d]pyrimidin-4(7H)-one
IId. Yield: 56%; M.P. 172–176°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 6.9–7.8 (m, 13H, Ar-H), 8.4 (s, 1H, C2-H), 12.40 (s, 1H, NH, D2O exchangeable): 13C NMR (DMSO-d
6): δ118.24, 119.37, 125.8, 126.18, 127.80, 128.45, 129.84, 130.29, 132.16, 132.70, 133.62, 134.96, 138.25, 142.05, 146.2, 163.15 ppm; IR (KBr) υ (cm−1): 3410, 3350 (NH2), 1720, 1705 (C=O), 1550(C=N); MS (EI)m/z: 432 (M+, 21.5%), 434 (M++ 2, 13.9%), 436 (M++ 4, 4.2%); Anal. Calcd for C24H15Cl2N3O (432.30): C, 66.68; H, 3.50; Cl, 16.40; N, 9.72; O, 3.70%. Found: C, 66.32; H, 3.18; Cl, 16.21; N, 9.50; O, 3.46%.7-(1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-5-phenyl-3H-pyrrolo[2,3-d]pyrimidin-4(7H)-one
IIe. Yield: 65%; M.P. 205–208°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.41 (s, 3H, CH3), 3.21 (s, 3H, N-CH3), 6.9–7.8 (m, 11H, Ar-H and C6-H), 8.32 (s, 1H, C2-H), 12.32 (s, 1H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3410, 3320 (NH2), 1720, 1680 (C=O), 1560(C=N) and disappearance of the CN group; MS (EI)m/z: 379 (M+, 23.5%), 380 (M++ 1, 7.1%); Anal. Calcd for C23H19N5O2 (379.43): C, 69.51; H, 4.82; N, 17.62; O, 8.05%. Found: C, 69.89; H, 5.16; N, 17.97; O, 8.41%.


#### 2.1.10. 7-Disubstituted-2-methyl-5-phenyl-7H-pyrrolo[2,3-d]pyrimidin-4(3H)-oneIIi, j (Scheme 2)

CompoundId ore (0.01 mol) in acetic acid/HCl (3 : 1) (30 mL) was refluxed for 12 h. The reaction mixture was cooled, poured onto ice/water, neutralized with ammonia to give a precipitate which was filtered, dried, and recrystallized from methanol to give the target compoundsII i,j.7-(3,4-Dichlorophenyl)-2-methyl-5,6-diphenyl-3H-pyrrolo[2,3-d]pyrimidin-4(7H)-one
II i. Yield: 67%; M.P. 200–202°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.35 (s, 3H, C2-CH3), 6.9–7.8 (m, 13H, Ar-H), 12.40 (s, 1H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3430, 3330 (NH2), 1710 (C=O), 1570 (C=N); MS (EI)m/z: 445 (M+, 26.2%), 447 (M++ 2, 15.3%), 449 (M++ 4, 1.04%); Anal. Calcd for C25H17Cl2N3O (445.07): C, 67.28; H, 3.84; Cl, 15.89; N, 9.41; O, 3.58%. Found: C, 67.45; H, 4.11; Cl, 16.22; N, 9.74; O, 3.82%.7-(1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-2-methyl-5-phenyl-3H-pyrrolo[2,3-d]pyrimidin-4(7H)-one
II j. Yield: 67%; M.P. 225–227°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.32 (s, 3H, C2-CH3), 2.41 (s, 3H, CH3), 3.22 (s, 3H, N-CH3), 7–7.8 (m, 11H, Ar-H and C6-H), 12.36 (s, 1H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3430, 3330 (NH2), 1730, 1700 (C=O), 1560 (C=N); MS (EI)m/z: 487 (M+, 45%), 488 (M++ 1, 15.2%); Anal. Calcd for C24H21N5O2 (411.46): C, 70.06; H, 5.14; N, 17.02; O, 7.78%. Found: C, 70.24; H, 5.32; N, 17.31; O, 7.96%.


#### 2.1.11.6,7-Disubstituted-5-phenyl-7H-pyrrolo[2,3-d]pyrimidin-4-ylaminesIIId, e (Scheme 2)

A suspension of the appropriate aminopyrroleI,d, ore (0.01 mol) and formamide (30 mL, 0.066 mol) were heated under reflux for 9 h, cooled, poured onto ice/water to give precipitates which were filtered off, dried, and recrystallized from ethanol to give the target compoundsIII d,e.7-(3,4-Dichlorophenyl)-5,6-diphenyl-7H-pyrrolo[2,3-d]pyrimidin-4-amine
III d. Yield: 63%; M.P. 115–118°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 5.4 (brs, 2H, NH2, D2O exchangeable), 7.1–7.7 (m, 13H, Ar-H), 8.2 (s, 1H, C2-H); IR (KBr) υ (cm−1): 3440, 3350 (NH2), 1570 (C=N), 1610 (C=C); MS (EI)m/z: 430 (M+, 31.2%), 432 (M++ 2, 17.6%), 434 (M++ 4, 0.98%); Anal. Calcd for C24H16Cl2N4 (430.08): C, 66.83; H, 3.74; Cl, 16.44; N, 12.99%. Found: C, 67.07; H, 5.11; Cl, 16.81; N, 13.36%.4-(4-Amino-5-phenyl-7H-pyrrolo[2,3-d]pyrimidin-7-yl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one
III e. Yield: 69%; M.P. 152–155°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.41 (s, 3H, CH3), 3.14 (s, 3H, N-CH3), 5.8 (brs, 2H, NH2, D2O exchangeable), 7.1–7.8 (m, 11H, Ar-H, and C6-H), 8.3 (s, 1H, C2-H); IR (KBr) υ (cm−1): 3430, 3330 (NH, NH2), 1705 (C=O), 1600 (C=C), 1540 (C=N); MS (EI)m/z: 396 (M+, 13.7%), 397 (M++ 1, 1.91%); Anal. Calcd for C23H20N6O (396.44): C, 69.68; H, 5.08; N, 21.20; O, 4.04%. Found: C, 69.42; H, 4.92; N, 20.89; O, 4.32%.


#### 2.1.12. 5-(5,6-Diphenyl-4-thioxo-3H-pyrrolo[2,3-d]pyrimidin-7(4H)-yl)-1,4-dimethyl-2-phenyl-1H -pyrazol-3(2H)-oneIIIi, j (Scheme 2)

CompoundI,d, ore (0.01 mol) and thiourea (1.2 g, 0.02 mol) were refluxed in dry ethanol (20 mL) for 12 h. The reaction mixture was evaporated under reduced pressure and the residues were recrystallized from methanol to give the target compoundsIII i,j.4-Amino-7-(3,4-dichlorophenyl)-5,6-diphenyl-1H-pyrrolo[2,3-d] pyrimidine-2(7H)-thione
IIIi. Yield: 70%; M.P. 90–95°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 6.62 (s, 2H, NH2, D2O exchangeable), 7.1–7.9 (m, 13H, Ar-H), 9.22 (s, 1H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3440, 3340 (NH, NH2), 1610 (NH–C=S); MS (EI)m/z: 463 (M+, 22.36%), 465 (M++ 2, 14.23%), 467 (M+ + 4, 4.54%); Anal. Calcd for C24H16Cl2N4S (463.38): C, 62.21; H, 3.48; Cl, 15.30; N, 12.09; S, 6.92%. Found: C, 62.45; H, 3.62; Cl, 15.49; N, 12.41; S, 7.21%.4-(4-Amino-5-phenyl-2-thioxo-1H-pyrrolo[2,3-d]pyrimidin-7(2H)-yl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one
IIIj. Yield: 74%; M.P. 172–174°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.34 (s, 3H, CH3), 3.11 (s, 3H, N-CH3), 6.51 (brs, 2H, NH2, D2O exchangeable), 7.1–7.8 (m, 11H, Ar-H, and C6-H), 8.3 (s, 1H, C2-H), 8.92 (s, 1H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3440, 3370 (NH, NH2), 1610 (C=C), 1600 (NH–C=S); MS (EI)m/z: 428 (M+, 14.8%), 429 (M+ + 1, 2.31%); Anal. Calcd for C23H20N6OS (428.51): C, 64.47; H, 4.70; N, 19.61; O, 3.73; S, 7.48%. Found: C, 64.78; H, 4.97; N, 19.92; O, 3.91; S, 7.62%.


#### 2.1.13. General Procedure for the Preparation of 4-ChloropyrrolopyrimidinesIVd–j (Scheme 2)

The appropriate compoundII (0.01 mol) was refluxed in phosphorus oxychloride (30 mL) for 12 h. The solution was cooled and poured with stirring onto ice/water and the formed precipitated was filtered, washed several times with water, dried, and recrystallized from ethanol to give the target compoundsIVd–j.4-Chloro-7-(3,4-dichlorophenyl)-5,6-diphenyl-7H-pyrrolo[2,3-d]pyrimidine
IVd. Yield: 76%; M.P. 124–128°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 6.9–7.8 (m, 13H, Ar-H), 8.6 (s, 1H, C2-H); 13C NMR (DMSO-d
6): δ117.5, 118.8, 126.18, 127.80, 128.45, 129.84, 130.21, 132.46, 132.64, 133.76, 134.84, 138.27, 141.05, 150.2, 151.24, 153.8 ppm; IR (KBr) υ (cm−1): 3080, 2840(CH), 1612 (C=C), 1580 (C=N); MS (EI)m/z: 449 (M+, 29.98%), 451 (M+ + 2, 23.6%), 453 (M+ + 4, 6.9%), 455 (M+ + 6, 0.66%); Anal. Calcd for C24H14Cl3N3 (449.03): C, 63.95; H, 3.13; Cl, 23.60; N, 9.32%. Found: C, 64.23; H, 3.42; Cl, 23.91; N, 9.49%.4-(4-Chloro-5-phenyl-7H-pyrrolo[2,3-d]pyrimidin-7-yl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one
IVe. Yield: 76%; M.P. 125–130°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.43 (s, 3H, CH3), 3.12 (s, 3H, N-CH3), 6.9–7.8 (m, 11H, Ar-H and C6-H), 8.5 (s, 1H, C2-H); IR (KBr) υ (cm−1): 3080, 2840 (CH), 1730 (C=O), 1612 (C=C), 1580 (C=N); MS (EI)m/z: 415 (M+, 20%), 417 (M++ 2, 5.5%); Anal. Calcd for C23H18ClN5O (415.87): C, 66.43; H, 4.36; Cl, 8.52; N, 16.84; O, 3.85%. Found: C, 66.67; H, 4.71; Cl, 8.68; N, 16.94; O, 3.99%.7-Benzyl-4-chloro-2-methyl-5,6-diphenyl-7H-pyrrolo[2,3-d]pyrimidine
IVf. Yield: 46%; M.P. 120–124°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.32 (s, 3H, CH3), 5.12 (s, 2H, Ph-CH2), 6.9–7.8 (m, 15H, Ar-H and C6-H); IR (KBr) υ (cm−1): 3080, 2840 (CH), 1610 (C=C), 1560 (C=N); MS (EI)m/z: 409 (M+, 14%), 411 (M+ + 2, 4.5%); Anal. Calcd for C26H20ClN3 (409.91): C, 76.18; H, 4.92; Cl, 8.65; N, 10.25%. Found: C, 76.47; H, 5.23; Cl, 8.96; N, 10.59%.4-(4-Chloro-2-methyl-5,6-diphenyl-7H-pyrrolo[2,3-d]pyrimidin-7-yl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one
IVg. Yield: 42%; M.P. 158–160°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.30–2.44 (s, 6H,2*CH3), 3.13 (s, 3H, N-CH3), 6.9–7.8 (m, 15H, Ar-H); IR (KBr) υ (cm−1): 3080, 2840 (CH), 1710 (C=O), 1605 (C=C), 1577 (C=N); MS (EI)m/z: 505 (M+, 13%), 507 (M+ + 2, 2.5%); Anal. Calcd for C30H24ClN5O (505.17): C, 71.21; H, 4.78; Cl, 7.01; N, 13.84; O, 3.16%. Found: C, 71.02; H, 4.97; Cl, 7.23; N, 14.06; O, 3.45%.4-Chloro-7-(3,4-dichlorophenyl)-2-methyl-5,6-diphenyl-7H-pyrrolo[2,3-d]pyrimidine
IVh. Yield: 45%; M.P. 108–110°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.36 (s, 3H, CH3), 7.2–7.8 (m, 13H, Ar-H); IR (KBr) υ (cm−1): 3080, 2840 (CH), 1600 (C=C), 1565 (C=N); MS (EI)m/z: 464 (M+, 11%), 466 (M+ + 2, 6.5%), 468 (M+ + 4, 2.3%), 394 (M+ + 6, 0.88%); Anal. Calcd for C25H16Cl3N3 (464.77): C, 64.61; H, 3.47; Cl, 22.88; N, 9.04%. Found: C, 64.99; H, 3.73; Cl, 23.08; N, 9.29%.4-(4-Chloro-2-methyl-5-phenyl-7H-pyrrolo[2,3-d]pyrimidin-7-yl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one
IVi. Yield: 42%; M.P. 95-100°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.28–2.46 (s, 6H, 2*CH3), 3.27 (s, 3H, N-CH3), 7.0–7.8 (m, 11H, Ar-H and C6-H); IR (KBr) υ (cm−1): 3070, 2850 (CH), 1700 (C=O), 1600 (C=C), 1570 (C=N); MS (EI)m/z: 429 (M+, 16%), 431 (M+ + 2, 4.7%); Anal. Calcd for C24H20ClN5O (429.90): C, 67.05; H, 4.69; Cl, 8.25; N, 16.29; O, 3.72%. Found: C, 67.42; H, 5.08; Cl, 8.57; N, 16.65; O, 4.02%.


#### 2.1.14. General Procedure for the Preparation of 4-HydrazinopyrrolopyrimidinesVd–i (Scheme 2)

Method A. CompoundIV (0.01 mol) and hydrazine hydrate (8 mL, 0.015 mol, 98%) were refluxed in dry ethanol (30 mL) for 12 h. The solvent was removed under reduced pressure and the residues were recrystallized from methanol to give the target compoundsV.Method B. CompoundsIi,j (0.01 mol) in dry toluene (20 mL) and hydrazine hydrate (5 mL, 0.015 mol, 98%) were added with stirring at room temperature for 14 h. The solvent was removed under reduced pressure, and the residue was recrystallized from methanol to giveVd,e; CompoundsVd,e prepared by this method are identical in all respects (physical and spectral data) to that prepared from Method A.7-(3,4-Dichlorophenyl)-4-hydrazinyl-5,6-diphenyl-7H-pyrrolo[2,3-d]pyrimidine
Vd. Yield: (A; 68%, B; 56%); M.P. 122–126°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 4.9–5.2 (brs, 2H, NH2, D2O exchangeable), 7.1–7.8 (m, 14H, Ar-H and NH, D2O exchangeable), 8.3 (s, 1H, C2-H); 13C NMR (DMSO-d
6): δ117.45, 118.69, 126.21, 127.47, 128.4, 129.74, 130.2, 132.39, 132.64, 133.76, 134.84, 138.27, 141.05, 153.2, 153.8, 168.71 ppm; IR (KBr) υ (cm−1): 3420, 3350 (NH2) 3210 (NH), 1610 (C=C), 1580 (C=N); MS (EI)m/z: 446 (M+, 23%), 448 (M+ + 2, 14%), 450 (M+ + 4, 3.4%); Anal. Calcd for C24H17Cl2N5 (446.33): C, 64.58; H, 3.84; Cl, 15.89; N, 15.69%. Found: C, 64.95; H, 4.20; Cl, 16.23; N, 16.04%.4-(4-Hydrazinyl-5-phenyl-7H-pyrrolo[2,3-d]pyrimidin-7-yl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one
Ve. Yield: (A) 71%, (B) 60%; M.P. 142–146°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.42 (s, 3H, CH3), 3.13 (s, 3H, N-CH3), 4.8–5.1 (brs, 2H, NH2, D2O exchangeable), 7.1–7.8 (m, 11H, Ar-H, C6-H and NH, D2O exchangeable), 8.2 (s, 1H, C2-H); IR (KBr) υ (cm−1): 3440, 3330 (NH2) 3260 (NH), 1705 (C=O), 1600 (C=C), 1580 (C=N); MS (EI)m/z: 411 (M+, 28%), 412 (M+ + 1, 6.5%); Anal. Calcd for C23H21N7O (411.46): C, 67.14; H, 5.14; N, 23.83; O, 3.89%. Found: C, 67.52; H, 5.48; N, 24.15; O, 4.52%.7-Benzyl-4-hydrazinyl-2-methyl-5,6-diphenyl-7H-pyrrolo[2,3-d] pyrimidine
Vf. Yield: 67%; M.P. 147–152°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.29 (s, 3H, CH3), 4.9–5.2 (brs, 2H, NH2, D2O exchangeable), 5.78 (s, 2H, Ph-CH2), 7.23–7.8 (m, 16H, Ar-H and NH, D2O exchangeable); IR (KBr) υ (cm−1): 3430, 3350 (NH2) 3250 (NH), 1605 (C=C), 1570 (C=N); MS (EI)m/z: 405 (M+, 29%), 406 (M+ + 1, 4.1%); Anal. Calcd for C26H23N5 (405.49): C, 77.01; H, 5.72; N, 17.27%. Found: C, 77.38; H, 6.05; N, 17.62%.4-(4-Hydrazinyl-2-methyl-5,6-diphenyl-7H-pyrrolo[2,3-d]pyrimidin-7-yl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one
Vg. Yield: 68%; M.P. 185–188°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.22–2.46 (s, 6H, 2*CH3), 3.11 (s, 3H, N-CH3), 4.34–4.8 (brs, 2H, NH2, D2O exchangeable), 7.2–7.8 (m, 16H, Ar-H and NH, D2O exchangeable): IR (KBr) υ (cm−1): 3420, 3350 (NH2) 3240 (NH), 1700 (C=O), 1605 (C=C), 1560 (C=N); MS (EI)m/z: 501 (M+, 31%), 502 (M++ 1, 5.4%); Anal. Calcd for C30H27N7O (501.58): C, 71.84; H, 5.43; N, 19.55; O, 3.19%. Found: C, 72.20; H, 5.81; N, 19.92; O, 3.55%.7-(3,4-Dichlorophenyl)-4-hydrazinyl-2-methyl-5,6-diphenyl-7H-pyrrolo[2,3-d]pyrimidine
Vh. Yield: 59%; M.P. 142–146 °C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.25 (s, 3H, CH3), 4.5–4.9 (brs, 2H, NH2, D2O exchangeable), 7.3–7.8 (m, 14H, Ar-H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3440, 3360 (NH2) 3250 (NH), 1610 (C=C), 1560 (C=N); MS (EI)m/z: 460 (M+, 31%), 462 (M+ + 2, 18%), 464 (M+ + 4, 4.9%); Anal. Calcd for C25H19Cl2N5 (460.36): C, 65.22; H, 4.16; Cl, 15.40; N, 15.21%. Found: C, 65.57; H, 4.52; Cl, 15.78; N, 15.56%.4-(4-Hydrazinyl-2-methyl-5-phenyl-7H-pyrrolo[2,3-d]pyrimidin-7-yl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one
Vi. Yield: 69%; M.P. 148–150°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.23–2.44 (s, 6H, 2*CH3), 3.13 (s, 3H, N-CH3), 4.4–4.78 (brs, 2H, NH2, D2O exchangeable), 7.2–7.8 (m, 12H, Ar-H, C6-H and NH, D2O exchangeable); IR (KBr) υ (cm−1): 3430, 3360 (NH2) 3250 (NH), 1705 (C=O), 1600 (C=C), 1580 (C=N); MS (EI)m/z: 501 (M+, 31%), 502 (M+ + 1, 5.4%); Anal. Calcd for C24H23N7O (425.49): C, 67.75; H, 5.45; N, 23.04; O, 3.76%. Found: C, 68.12; H, 5.76; N, 23.37; O, 4.11%.


#### 2.1.15. General Procedure for the Preparation of 4-ThienopyrrolopyrimidineVI d–f (Scheme 2)

CompoundIII (0.01 mol) and thiourea (1.2 g, 0.02 mol) were refluxed in dry ethanol (20 mL) for 14 h. The reaction mixture was evaporated under reduced pressure and the residues were recrystallized from methanol to give the target compoundsVI.7-(3,4-Dichlorophenyl)-5,6-diphenyl-3H-pyrrolo[2,3-d]pyrimidine-4(7H)-thione
VId. Yield: 66%; M.P. 142–166°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 7.3–7.8 (m, 13H, Ar-H), 9.02 (s, 1H, C2-H), 11.71 (s, 1H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3250 (NH), 1630 (NH–C=S), 1560 (C=N); MS (EI)m/z: 447 (M+, 28%), 449 (M+ + 2, 18%), 451 (M++ 4, 0.98%); Anal. Calcd for C24H15Cl2N3S (447.04): C, 64.29; H, 3.37; Cl, 15.81; N, 9.37; S, 7.15%. Found: C, 64.64; H, 3.74; Cl, 16.14; N, 9.73; S, 7.52%.1,5-Dimethyl-2-phenyl-4-(5-phenyl-4-thioxo-3H-pyrrolo[2,3-d]pyrimidin-7(4H)-yl)-1H-pyrazol-3(2H)-one
VIe. Yield: 61%; M.P. 142–166°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.44 (s, 3H, CH3), 3.13 (s, 3H, N-CH3), 7.2–7.8 (m, 11H, Ar-H, and C6-H) 9.12 (s, 1H, C2-H), 12.10 (s, 1H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3230 (NH), 1700 (C=O), 1610 (NH–C=S), 1550 (C=N); MS (EI)m/z: 413 (M+, 30%), 414 (M+ + 1, 8.4%); Anal. Calcd for C23H19N5OS (413.49): C, 66.81; H, 4.63; N, 16.94; O, 3.87; S, 7.75%. Found: C, 67.16; H, 4.98; N, 17.31; O, 4.24; S, 8.12%.7-Benzyl-2-methyl-5,6-diphenyl-3H-pyrrolo[2,3-d]pyrimidine-4(7H)-thione
VIf. Yield: 47%; M.P. 165–167°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.29 (s, 3H, CH3), 5.78 (s, 2H, Ph-CH2), 7.23–7.8 (m, 16H, Ar-H and NH, D2O exchangeable); IR (KBr) υ (cm−1): 3250 (NH), 1605 (NH–C=S), 1570 (C=N); MS (EI)m/z: 407 (M+, 26%), 408 (M++ 1, 3.91%), 409 (M++ 2, 0.81%); Anal. Calcd for C26H21N3S (407.53): C, 76.63; H, 5.19; N, 10.31; S, 7.87%. Found: C, 76.56; H, 5.11; N, 10.26; S, 7.80%.


#### 2.1.16. General Procedure for the Preparation of Substituted Carbonohydrazonoyl DerivativesVII (Scheme 3)

A mixture ofI (0.01 mol) in concentrated HCl (10 ml) was cooled with stirring to 0–5°C under ice, and cooled sodium nitrite solution (2.5 g in 10 mL of water) was added to it dropwise during 30 minutes. The reaction mixture was then stirred for 30 minutes. Without separation, an ice-cold mixture of active methylene compounds (malononitrile and/or ethyl cyanoacetate) (0.015 mol) and sodium acetate (4.10 g; 0.05 mole) in ethanol (50 mL) were added dropwise with stirring for 15 min. The stirring was continued for 30 minutes under ice and the reaction mixture was then left for 12 h at room temperature. The precipitate was filtered off and recrystallized from ethanol/H2O to giveVII.(3-Cyano-1-(3,4-dichlorophenyl)-4,5-diphenyl-1H-pyrrol-2-yl)carbon-hydrazonoyl dicyanide
VIId. Yield: 56%; M.P. 102–106°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 6.71 (s, 1H, NH, hydrazone, D2O exchangeable), 7.3–7.8 (m, 13H, Ar-H); IR (KBr) υ (cm−1): 3290 (NH), 2320 (C≡N), 1695 (C=O), 1585 (C=N); MS (EI)m/z: 481 (M+, 19%), 482 (M+ + 2, 12.8%), 483 (M+ + 4, 2.3%); Anal. Calcd for C26H14Cl2N6 (481.33): C, 64.88; H, 2.93; Cl, 14.73; N, 17.46%. Found: C, 64.67; H, 2.78; Cl, 14.51; N, 17.12%.(3-Cyano-1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-4-phenyl-1H-pyrrol-2-yl)carbonohydrazonoyl dicyanide
VIIe. Yield: 51%; M.P. 110–114°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.42 (s, 3H, CH3), 3.11 (s, 3H, N-CH3), 6.71 (s, 1H, NH, hydrazone, D2O exchangeable), 7.2–7.8 (m, 11H, Ar-H, and C6-H); IR (KBr) υ (cm−1): 3290 (NH), 2320 (C≡N), 1695 (C=O), 1585 (C=N); MS (EI)m/z: 446 (M+, 17.8%), 447 (M+ + 1, 8.21%); Anal. Calcd for C25H18N8O (446.46): C, 67.25; H, 4.06; N, 25.10; O, 3.58%. Found: C, 67.54; H, 4.12; N, 25.23; O, 3.69%.Ethyl 2-(2-(1-Benzyl-3-cyano-4,5-diphenyl-1H-pyrrol-2-yl)hydrazono)-2-cyano-acetate
VIIf. Yield: 48%; M.P. 125–130°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 1.31 (t, 3H, J = 6.8, CH2-CH3*), 4.4 (q, 2H, J = 6.8, O-CH2), 5.62 (s, 2H, Ph-CH2), 6.8 (s, 1H, NH, hydrazone, D2O exchangeable), 7.2–7.8 (m, 15H, Ar-H, and C6-H); IR (KBr) υ (cm−1): 3290 (NH), 2320 (C≡N), 1695 (C=O), 1585 (C=N); MS (EI)m/z: 473 (M+, 18%), 474 (M+ + 1, 5.1%); Anal. Calcd for C29H23N5O2 (473.53): C, 73.56; H, 4.90; N, 14.79; O, 6.76%. Found: C, 73.48; H, 4.64; N, 14.63; O, 6.70%.


#### 2.1.17. General Procedure for the Preparation of Pyrazolyl DerivativesVIII (Scheme 3)

A mixture of compoundVII (0.01 mol) and hydrazine hydrate (0.64 ml, 0.02 mole) in ethanol (30 mL) were heated under reflux for 8 h controlled by TLC. The solvent was concentrated and the reaction product was allowed to cool then pour on acidified ice/H2O. The product was filtered off, washed with water, dried, and recrystallized from ethanol to giveVIII.2-(2-(3,5-Diamino-4H-pyrazol-4-ylidene)hydrazinyl)-1-(3,4-dichloro phenyl)-4,5-diphenyl-1H-pyrrole-3-carbonitrile
VIIId. Yield: 55%; M.P. 120–124°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 6.5 (s, 4H, 2*NH2, D2O exchangeable), 7.2–8 (m, 14H, Ar-H and NH, hydrazone, D2O exchangeable); IR (KBr) υ (cm−1): 3350–3280 (broad NH and NH2), 2320 (C≡N), 1695 (C=O), 1585 (C=N); MS (EI)m/z: 513 (M+, 12%), 515 (M+ + 2, 7.8%), 516 (M+ + 4, 2.4%); Anal. Calcd for C26H17Cl2N7O (513.09): C, 60.71; H, 3.33; Cl, 13.79; N, 19.06; O, 3.11%. Found: C, 60.98; H, 3.41; Cl, 13.95; N, 19.43; O, 3.27%.2-(2-(3,5-Diamino-4H-pyrazol-4-ylidene)hydrazinyl)-1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-4-phenyl-1H-pyrrole-3-carbonitrile
VIIIe. Yield: 61%; M.P. 135–138°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.42 (s, 3H, CH3), 3.11 (s, 3H, N-CH3), 6.48 (s, 4H, 2*NH2, D2O exchangeable), 6.89 (s, 1H, NH, hydrazone, D2O exchangeable), 7.3–8 (m, 11H, Ar-H, and C6-H); IR (KBr) υ (cm−1): 3340–3290 (broad NH and NH2), 2320 (C≡N), 1695 (C=O), 1585 (C=N); MS (EI)m/z: 478 (M+, 15.2%), 479 (M+ + 1, 4.46%); Anal. Calcd for C25H22N10O (478.51): C, 62.75; H, 4.63; N, 29.27; O, 3.34%. Found: C, 62.64; H, 4.47; N, 29.02; O, 3.09%.2-(2-(3-Amino-5-hydroxy-4H-pyrazol-4-ylidene)hydrazinyl)-1-benzyl-4,5-diphenyl-1H-pyrrole-3-carbonitrile
VIIIf. Yield: 56%; M.P. 97–100°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 5.61 (s, 2H, CH2), 6.45 (s, 4H, 2*NH2, D2O exchangeable), 6.8 (s, 1H, NH, hydrazone, D2O exchangeable), 7.2–7.9 (m, 15H, Ar-H).; IR (KBr) υ (cm−1): 3340–3270 (broad NH and NH2), 2310 (C≡N), 1690 (C=O), 1575 (C=N); MS (EI)m/z: 459 (M+, 10%), 460 (M+ + 1, 2.91%); Anal. Calcd for C27H21N7O (459.50): C, 70.57; H, 4.61; N, 21.34; O, 3.48%. Found: C, 70.65; H, 4.69; N, 21.07; O, 3.41%.


## 2.1. Chemistry

All melting points were uncorrected and measured using Electrothermal IA 9100 apparatus (Shimadzu, Japan). IR spectra were recorded as potassium bromide pellets on a Perkin-Elmer 1650 spectrophotometer (USA), Faculty of Science, Cairo University, Cairo, Egypt.1H NMR and 13CNMR spectra were performed on JOEL NMR FXQ-300 MHz and JOELNMR FXQ-500 MHz spand chemical shifts were expressed as ppm against TMS as internal reference (Faculty of Science, Cairo University, Cairo, Egypt). Mass spectra were recorded at 70 eV EI Ms-QP 1000 EX (Shimadzu, Japan), Faculty of Science, Cairo University, Cairo, Egypt. Microanalyses were operated using Vario, Elementar apparatus (Shimadzu, Japan), Organic Microanalysis Unit, Faculty of Science, Cairo University, Cairo, Egypt. Column chromatography was performed on (Merck) silica gel 60 (particle size 0.06–0.20 mm). CompoundsIa–c,f–h,k–m,IIa–c,f–h,IIIa–c,f–h,IVa–c,Va–c,VIa–c,VIIa–c,andVIIIa–c were prepared as reported in the literature [26–31]. All new compounds yielded spectral data consistent with the proposed structure and microanalysis within ± 0.4% of the theoretical values.


### 2.1.1. 2-Amino-1-(3,4-dichlorophenyl)-4,5-diphenyl-1H-pyrrole-3-carbonitrileId (Scheme 1)

A mixture of benzoin (2 g, 0.01 mol), 3,4-dichlorophenyl amine (1.6 g, 0.01 mol) in dry benzene (50 mL), was kept at 80°C for 9 h. The reaction mixture was cooled; then malononitrile (0.66 mg, 0.01 mol) was added, followed by catalytic amount of pyridine (2 mL) portion wise and left to reflex till solid formed. The solvent was evaporated under reduced pressure and the residue was recrystallized from methanol to giveId. Yield: 45%; M.P. 118–122°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 5.21 (br.s, 2H, NH2, D2O exchangeable), 7.0–7.8 (m, 13H, Ar-H); 13C NMR (DMSO-d
6): δ 114.33, 118.24, 119.37, 125.8, 126.18, 127.80, 128.45, 129.84, 130.29, 132.16, 132.70, 133.62, 134.96, 142.05 ppm; IR (KBr) υ (cm−1): 3410, 3370 (NH2), 2220 (C≡N); MS (EI)m/z: 403 (M+, 14%), 405 (M++ 2, 8.75%), 407 (M++ 4, 1.1%); Anal. Calcd for C23H15Cl2N3 (403.06): C, 68.33; H, 3.74; Cl, 17.54; N, 10.39%. Found: C, 68.55; H, 3.92; Cl, 17.23; N, 10.72%.


### 2.1.2. 2-Amino-1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H -pyrazol-4-yl)-4-phenyl-1H -pyrrole-3-carbonitrileIe (Scheme 1)

1,5-Dimethyl-4-(2-oxo-2-phenylethylamino)-2-phenyl-1H-pyrazol-3(2H)-one [27–30](3.22 g, 0.01 mol) was dissolved in dry ethanol (20 mL); then malononitrile (0.66 g, 0.01 mol) was added, followed by sodium ethoxide (0.01 mol) portion wise, and left to reflux till solid formed. The solvent was evaporated under reduced pressure and the residue was recrystallized from methanol to giveIe.Yield: 66%; M.P. 163–166°C;1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.43 (s, 3H, CH3), 3.12 (s, 3H, N-CH3), 6.13 (br.s, 2H, NH2, D2O exchangeable), 6.8–7.8 (m, 10H, Ar-H and 1H, C6-H); IR (KBr) υ (cm−1): 3410, 3350 (NH2), 2210 (C≡N), 1703 (C=O); MS (EI)m/z: 369 (M+, 23%), 370 (M++ 1, 6.1%); Anal. Calcd for C22H19N5O (369.16): C, 71.53; H, 5.18; N, 18.96; O, 4.33%. Found: C, 71.55; H, 5.26; N, 18.70; O, 3.05%.


### 2.1.3. 2-Ethoxymethylenamino-1,5-disubstituted-4-phenyl-1H -pyrrole-3-carbonitrilesIi,j (Scheme 1)

CompoundI,d,or e (0.01 mol) in triethyl orthoformate (20 mL) was refluxed for 9 h. The solvent was removed under reduced pressure and the residue was recrystallized from methanol/water to give the target compoundsIi,j.


### 2.1.4. Ethyl N-3-Cyano-1-(3,4-dichlorophenyl)-4,5-diphenyl-1H -pyrrol-2-ylformimidateIi

Yield: 60%; M.P. 120–122°C;1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 1.30 (t, 3H,J = 7.1 Hz, CH3), 4.2 (q, 2H,J= 7.1 Hz, OCH2), 6.9–7.8 (m, 14H, Ar-H and N=CH); IR (KBr) υ (cm−1): 3070, 2900(CH), 2310(CN), 1620 (C=C), 1560 (C=N); MS (EI)m/z: 460 (M+, 13.5%), 462 (M++ 2, 8.5%), 464 (M++ 4, 2.71%); Anal. Calcd for C26H19Cl2N3O (460.35): C, 67.83; H, 4.16; Cl, 15.40; N, 9.13; O, 3.48%, Found: C, 68.03; H, 4.11; Cl, 15.63; N, 8.91; O, 3.69%.


### 2.1.5. Ethyl N-3-Cyano-1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H -pyrazol-4-yl)-4-phenyl-1H -pyrrol-2-ylacetimidateIj

Yield: 56%; M.P. 120–122°C;1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 1.20 (t, 3H,J = 7.2 Hz, CH3), 2.41 (s, 3H, CH3), 3.1 (s, 3H, N-CH3), 4.01 (q, 2H,J= 7.1 Hz, OCH2), 6.9–7.8 (m, 12H, Ar-H, C6-H and N=CH); IR (KBr) υ (cm−1): 3030, 2910(CH), 2240(CN), 1610 (C=C), 1570 (C=N); MS (EI)m/z: 425 (M+, 6.5%), 426 (M++ 1, 1.81%); Anal. Calcd for C26H23N5O2 (425.19): C, 70.57; H, 5.45; N, 16.46; O, 7.52%. Found: C, 70.21; H, 5.17; N, 16.12; O, 7.18%.


### 2.1.6. N-(4-Phenyl-1,3,5-trisubstituted-1H -pyrrol-2-yl)-acetamidesI n,o (Scheme 1)

CompoundI,d, ore (0.01 mol) in acetic anhydride (30 mL) was refluxed for 2 h, cooled, poured onto ice water, neutralized with ammonia to give a precipitate which was filtered off, dried, and recrystallized from methanol to give the target compoundsIn,o.


### 2.1.7. N-(3-Cyano-1-(3,4-dichlorophenyl)-4,5-diphenyl-1H -pyrrol-2-yl) acetamideIn

Yield: 66%; M.P. 135–138°C;1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.23 (s, 3H, CO-CH3), 7.0–7.8 (m, 13H, Ar-H), 9.5 (s, 1H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3430 (NH), 2330 (C≡N), 1710 (C=O); MS (EI)m/z: 445 (M+, 13.1%), 447 (M+ + 2, 7.9%), 449 (M+ + 4, 0.91%); Anal. Calcd for C25H17Cl2N3O (445.07): C, 67.28; H, 3.84; Cl, 15.89; N, 9.41; O, 3.58%. Found: C, 67.47; H, 4.06; Cl, 16.22; N, 9.57; O, 3.66%.


### 2.1.8. N-(3-Cyano-1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H -pyrazol-4-yl)-4-phenyl-1H -pyrrol-2-yl)acetamideIo

Yield: 72%; M.P. 135–138°C;1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.23 (s, 3H, CO-CH3), 2.43 (s, 3H, CH3), 3.12 (s, 3H, N-CH3), 7.0–7.8 (m, 11H, Ar-H and C6-H), 9.4 (s, 1H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3350 (NH), 2310 (C≡N), 1715, 1705 (C=O); MS (EI)m/z: 411 (M+, 15.4%), 412 (M++ 1, 3.73%); Anal. Calcd for C24H21N5O2 (411.17): C, 70.06; H, 5.14; N, 17.02; O, 7.78%. Found: C, 70.37; H, 5.45; N, 17.34; O, 7.95%.


### 2.1.9. 7-(2,4-Dimethyl-5-oxo-1-phenyl-2,5-dihydro-1H -pyrazol-3-yl)-5,6-diphenyl -3H-pyrrolo[2,3-d]pyrimidin-4(7H)-oneIId,e (Scheme 2)

Scheme 2
Synthetic pathways for compoundsI–VI: reagents and conditions: (1) HCO2H; (2) AcOH/HCl; (3) HCONH2; (4) NH2CSNH2; (5) POCl3; (6) N2H4·H2O; and (7) NH2CSNH2.Scheme 3
Synthetic pathways for compoundsVII–VIII: reagents and conditions: (1) NaNO2/HCl/Stirring (75 min); (2) NCCH2Y/CH3CO2NH4/EtOH; and (3) N2H4
·H2O.CompoundId ore (0.01 mol) in formic acid (20 mL, 85%) was refluxed for 12 h. The reaction mixture was cooled, poured onto ice/water to give a precipitate which was filtered, dried, and recrystallized from ethanol to give the target compoundsIId,e.7-(3,4-Dichlorophenyl)-5,6-diphenyl-3H-pyrrolo[2,3-d]pyrimidin-4(7H)-one
IId. Yield: 56%; M.P. 172–176°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 6.9–7.8 (m, 13H, Ar-H), 8.4 (s, 1H, C2-H), 12.40 (s, 1H, NH, D2O exchangeable): 13C NMR (DMSO-d
6): δ118.24, 119.37, 125.8, 126.18, 127.80, 128.45, 129.84, 130.29, 132.16, 132.70, 133.62, 134.96, 138.25, 142.05, 146.2, 163.15 ppm; IR (KBr) υ (cm−1): 3410, 3350 (NH2), 1720, 1705 (C=O), 1550(C=N); MS (EI)m/z: 432 (M+, 21.5%), 434 (M++ 2, 13.9%), 436 (M++ 4, 4.2%); Anal. Calcd for C24H15Cl2N3O (432.30): C, 66.68; H, 3.50; Cl, 16.40; N, 9.72; O, 3.70%. Found: C, 66.32; H, 3.18; Cl, 16.21; N, 9.50; O, 3.46%.7-(1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-5-phenyl-3H-pyrrolo[2,3-d]pyrimidin-4(7H)-one
IIe. Yield: 65%; M.P. 205–208°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.41 (s, 3H, CH3), 3.21 (s, 3H, N-CH3), 6.9–7.8 (m, 11H, Ar-H and C6-H), 8.32 (s, 1H, C2-H), 12.32 (s, 1H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3410, 3320 (NH2), 1720, 1680 (C=O), 1560(C=N) and disappearance of the CN group; MS (EI)m/z: 379 (M+, 23.5%), 380 (M++ 1, 7.1%); Anal. Calcd for C23H19N5O2 (379.43): C, 69.51; H, 4.82; N, 17.62; O, 8.05%. Found: C, 69.89; H, 5.16; N, 17.97; O, 8.41%.


### 2.1.10. 7-Disubstituted-2-methyl-5-phenyl-7H-pyrrolo[2,3-d]pyrimidin-4(3H)-oneIIi, j (Scheme 2)

CompoundId ore (0.01 mol) in acetic acid/HCl (3 : 1) (30 mL) was refluxed for 12 h. The reaction mixture was cooled, poured onto ice/water, neutralized with ammonia to give a precipitate which was filtered, dried, and recrystallized from methanol to give the target compoundsII i,j.7-(3,4-Dichlorophenyl)-2-methyl-5,6-diphenyl-3H-pyrrolo[2,3-d]pyrimidin-4(7H)-one
II i. Yield: 67%; M.P. 200–202°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.35 (s, 3H, C2-CH3), 6.9–7.8 (m, 13H, Ar-H), 12.40 (s, 1H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3430, 3330 (NH2), 1710 (C=O), 1570 (C=N); MS (EI)m/z: 445 (M+, 26.2%), 447 (M++ 2, 15.3%), 449 (M++ 4, 1.04%); Anal. Calcd for C25H17Cl2N3O (445.07): C, 67.28; H, 3.84; Cl, 15.89; N, 9.41; O, 3.58%. Found: C, 67.45; H, 4.11; Cl, 16.22; N, 9.74; O, 3.82%.7-(1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-2-methyl-5-phenyl-3H-pyrrolo[2,3-d]pyrimidin-4(7H)-one
II j. Yield: 67%; M.P. 225–227°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.32 (s, 3H, C2-CH3), 2.41 (s, 3H, CH3), 3.22 (s, 3H, N-CH3), 7–7.8 (m, 11H, Ar-H and C6-H), 12.36 (s, 1H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3430, 3330 (NH2), 1730, 1700 (C=O), 1560 (C=N); MS (EI)m/z: 487 (M+, 45%), 488 (M++ 1, 15.2%); Anal. Calcd for C24H21N5O2 (411.46): C, 70.06; H, 5.14; N, 17.02; O, 7.78%. Found: C, 70.24; H, 5.32; N, 17.31; O, 7.96%.


### 2.1.11.6,7-Disubstituted-5-phenyl-7H-pyrrolo[2,3-d]pyrimidin-4-ylaminesIIId, e (Scheme 2)

A suspension of the appropriate aminopyrroleI,d, ore (0.01 mol) and formamide (30 mL, 0.066 mol) were heated under reflux for 9 h, cooled, poured onto ice/water to give precipitates which were filtered off, dried, and recrystallized from ethanol to give the target compoundsIII d,e.7-(3,4-Dichlorophenyl)-5,6-diphenyl-7H-pyrrolo[2,3-d]pyrimidin-4-amine
III d. Yield: 63%; M.P. 115–118°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 5.4 (brs, 2H, NH2, D2O exchangeable), 7.1–7.7 (m, 13H, Ar-H), 8.2 (s, 1H, C2-H); IR (KBr) υ (cm−1): 3440, 3350 (NH2), 1570 (C=N), 1610 (C=C); MS (EI)m/z: 430 (M+, 31.2%), 432 (M++ 2, 17.6%), 434 (M++ 4, 0.98%); Anal. Calcd for C24H16Cl2N4 (430.08): C, 66.83; H, 3.74; Cl, 16.44; N, 12.99%. Found: C, 67.07; H, 5.11; Cl, 16.81; N, 13.36%.4-(4-Amino-5-phenyl-7H-pyrrolo[2,3-d]pyrimidin-7-yl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one
III e. Yield: 69%; M.P. 152–155°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.41 (s, 3H, CH3), 3.14 (s, 3H, N-CH3), 5.8 (brs, 2H, NH2, D2O exchangeable), 7.1–7.8 (m, 11H, Ar-H, and C6-H), 8.3 (s, 1H, C2-H); IR (KBr) υ (cm−1): 3430, 3330 (NH, NH2), 1705 (C=O), 1600 (C=C), 1540 (C=N); MS (EI)m/z: 396 (M+, 13.7%), 397 (M++ 1, 1.91%); Anal. Calcd for C23H20N6O (396.44): C, 69.68; H, 5.08; N, 21.20; O, 4.04%. Found: C, 69.42; H, 4.92; N, 20.89; O, 4.32%.


### 2.1.12. 5-(5,6-Diphenyl-4-thioxo-3H-pyrrolo[2,3-d]pyrimidin-7(4H)-yl)-1,4-dimethyl-2-phenyl-1H -pyrazol-3(2H)-oneIIIi, j (Scheme 2)

CompoundI,d, ore (0.01 mol) and thiourea (1.2 g, 0.02 mol) were refluxed in dry ethanol (20 mL) for 12 h. The reaction mixture was evaporated under reduced pressure and the residues were recrystallized from methanol to give the target compoundsIII i,j.4-Amino-7-(3,4-dichlorophenyl)-5,6-diphenyl-1H-pyrrolo[2,3-d] pyrimidine-2(7H)-thione
IIIi. Yield: 70%; M.P. 90–95°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 6.62 (s, 2H, NH2, D2O exchangeable), 7.1–7.9 (m, 13H, Ar-H), 9.22 (s, 1H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3440, 3340 (NH, NH2), 1610 (NH–C=S); MS (EI)m/z: 463 (M+, 22.36%), 465 (M++ 2, 14.23%), 467 (M+ + 4, 4.54%); Anal. Calcd for C24H16Cl2N4S (463.38): C, 62.21; H, 3.48; Cl, 15.30; N, 12.09; S, 6.92%. Found: C, 62.45; H, 3.62; Cl, 15.49; N, 12.41; S, 7.21%.4-(4-Amino-5-phenyl-2-thioxo-1H-pyrrolo[2,3-d]pyrimidin-7(2H)-yl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one
IIIj. Yield: 74%; M.P. 172–174°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.34 (s, 3H, CH3), 3.11 (s, 3H, N-CH3), 6.51 (brs, 2H, NH2, D2O exchangeable), 7.1–7.8 (m, 11H, Ar-H, and C6-H), 8.3 (s, 1H, C2-H), 8.92 (s, 1H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3440, 3370 (NH, NH2), 1610 (C=C), 1600 (NH–C=S); MS (EI)m/z: 428 (M+, 14.8%), 429 (M+ + 1, 2.31%); Anal. Calcd for C23H20N6OS (428.51): C, 64.47; H, 4.70; N, 19.61; O, 3.73; S, 7.48%. Found: C, 64.78; H, 4.97; N, 19.92; O, 3.91; S, 7.62%.


### 2.1.13. General Procedure for the Preparation of 4-ChloropyrrolopyrimidinesIVd–j (Scheme 2)

The appropriate compoundII (0.01 mol) was refluxed in phosphorus oxychloride (30 mL) for 12 h. The solution was cooled and poured with stirring onto ice/water and the formed precipitated was filtered, washed several times with water, dried, and recrystallized from ethanol to give the target compoundsIVd–j.4-Chloro-7-(3,4-dichlorophenyl)-5,6-diphenyl-7H-pyrrolo[2,3-d]pyrimidine
IVd. Yield: 76%; M.P. 124–128°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 6.9–7.8 (m, 13H, Ar-H), 8.6 (s, 1H, C2-H); 13C NMR (DMSO-d
6): δ117.5, 118.8, 126.18, 127.80, 128.45, 129.84, 130.21, 132.46, 132.64, 133.76, 134.84, 138.27, 141.05, 150.2, 151.24, 153.8 ppm; IR (KBr) υ (cm−1): 3080, 2840(CH), 1612 (C=C), 1580 (C=N); MS (EI)m/z: 449 (M+, 29.98%), 451 (M+ + 2, 23.6%), 453 (M+ + 4, 6.9%), 455 (M+ + 6, 0.66%); Anal. Calcd for C24H14Cl3N3 (449.03): C, 63.95; H, 3.13; Cl, 23.60; N, 9.32%. Found: C, 64.23; H, 3.42; Cl, 23.91; N, 9.49%.4-(4-Chloro-5-phenyl-7H-pyrrolo[2,3-d]pyrimidin-7-yl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one
IVe. Yield: 76%; M.P. 125–130°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.43 (s, 3H, CH3), 3.12 (s, 3H, N-CH3), 6.9–7.8 (m, 11H, Ar-H and C6-H), 8.5 (s, 1H, C2-H); IR (KBr) υ (cm−1): 3080, 2840 (CH), 1730 (C=O), 1612 (C=C), 1580 (C=N); MS (EI)m/z: 415 (M+, 20%), 417 (M++ 2, 5.5%); Anal. Calcd for C23H18ClN5O (415.87): C, 66.43; H, 4.36; Cl, 8.52; N, 16.84; O, 3.85%. Found: C, 66.67; H, 4.71; Cl, 8.68; N, 16.94; O, 3.99%.7-Benzyl-4-chloro-2-methyl-5,6-diphenyl-7H-pyrrolo[2,3-d]pyrimidine
IVf. Yield: 46%; M.P. 120–124°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.32 (s, 3H, CH3), 5.12 (s, 2H, Ph-CH2), 6.9–7.8 (m, 15H, Ar-H and C6-H); IR (KBr) υ (cm−1): 3080, 2840 (CH), 1610 (C=C), 1560 (C=N); MS (EI)m/z: 409 (M+, 14%), 411 (M+ + 2, 4.5%); Anal. Calcd for C26H20ClN3 (409.91): C, 76.18; H, 4.92; Cl, 8.65; N, 10.25%. Found: C, 76.47; H, 5.23; Cl, 8.96; N, 10.59%.4-(4-Chloro-2-methyl-5,6-diphenyl-7H-pyrrolo[2,3-d]pyrimidin-7-yl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one
IVg. Yield: 42%; M.P. 158–160°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.30–2.44 (s, 6H,2*CH3), 3.13 (s, 3H, N-CH3), 6.9–7.8 (m, 15H, Ar-H); IR (KBr) υ (cm−1): 3080, 2840 (CH), 1710 (C=O), 1605 (C=C), 1577 (C=N); MS (EI)m/z: 505 (M+, 13%), 507 (M+ + 2, 2.5%); Anal. Calcd for C30H24ClN5O (505.17): C, 71.21; H, 4.78; Cl, 7.01; N, 13.84; O, 3.16%. Found: C, 71.02; H, 4.97; Cl, 7.23; N, 14.06; O, 3.45%.4-Chloro-7-(3,4-dichlorophenyl)-2-methyl-5,6-diphenyl-7H-pyrrolo[2,3-d]pyrimidine
IVh. Yield: 45%; M.P. 108–110°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.36 (s, 3H, CH3), 7.2–7.8 (m, 13H, Ar-H); IR (KBr) υ (cm−1): 3080, 2840 (CH), 1600 (C=C), 1565 (C=N); MS (EI)m/z: 464 (M+, 11%), 466 (M+ + 2, 6.5%), 468 (M+ + 4, 2.3%), 394 (M+ + 6, 0.88%); Anal. Calcd for C25H16Cl3N3 (464.77): C, 64.61; H, 3.47; Cl, 22.88; N, 9.04%. Found: C, 64.99; H, 3.73; Cl, 23.08; N, 9.29%.4-(4-Chloro-2-methyl-5-phenyl-7H-pyrrolo[2,3-d]pyrimidin-7-yl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one
IVi. Yield: 42%; M.P. 95-100°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.28–2.46 (s, 6H, 2*CH3), 3.27 (s, 3H, N-CH3), 7.0–7.8 (m, 11H, Ar-H and C6-H); IR (KBr) υ (cm−1): 3070, 2850 (CH), 1700 (C=O), 1600 (C=C), 1570 (C=N); MS (EI)m/z: 429 (M+, 16%), 431 (M+ + 2, 4.7%); Anal. Calcd for C24H20ClN5O (429.90): C, 67.05; H, 4.69; Cl, 8.25; N, 16.29; O, 3.72%. Found: C, 67.42; H, 5.08; Cl, 8.57; N, 16.65; O, 4.02%.


### 2.1.14. General Procedure for the Preparation of 4-HydrazinopyrrolopyrimidinesVd–i (Scheme 2)

Method A. CompoundIV (0.01 mol) and hydrazine hydrate (8 mL, 0.015 mol, 98%) were refluxed in dry ethanol (30 mL) for 12 h. The solvent was removed under reduced pressure and the residues were recrystallized from methanol to give the target compoundsV.Method B. CompoundsIi,j (0.01 mol) in dry toluene (20 mL) and hydrazine hydrate (5 mL, 0.015 mol, 98%) were added with stirring at room temperature for 14 h. The solvent was removed under reduced pressure, and the residue was recrystallized from methanol to giveVd,e; CompoundsVd,e prepared by this method are identical in all respects (physical and spectral data) to that prepared from Method A.7-(3,4-Dichlorophenyl)-4-hydrazinyl-5,6-diphenyl-7H-pyrrolo[2,3-d]pyrimidine
Vd. Yield: (A; 68%, B; 56%); M.P. 122–126°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 4.9–5.2 (brs, 2H, NH2, D2O exchangeable), 7.1–7.8 (m, 14H, Ar-H and NH, D2O exchangeable), 8.3 (s, 1H, C2-H); 13C NMR (DMSO-d
6): δ117.45, 118.69, 126.21, 127.47, 128.4, 129.74, 130.2, 132.39, 132.64, 133.76, 134.84, 138.27, 141.05, 153.2, 153.8, 168.71 ppm; IR (KBr) υ (cm−1): 3420, 3350 (NH2) 3210 (NH), 1610 (C=C), 1580 (C=N); MS (EI)m/z: 446 (M+, 23%), 448 (M+ + 2, 14%), 450 (M+ + 4, 3.4%); Anal. Calcd for C24H17Cl2N5 (446.33): C, 64.58; H, 3.84; Cl, 15.89; N, 15.69%. Found: C, 64.95; H, 4.20; Cl, 16.23; N, 16.04%.4-(4-Hydrazinyl-5-phenyl-7H-pyrrolo[2,3-d]pyrimidin-7-yl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one
Ve. Yield: (A) 71%, (B) 60%; M.P. 142–146°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.42 (s, 3H, CH3), 3.13 (s, 3H, N-CH3), 4.8–5.1 (brs, 2H, NH2, D2O exchangeable), 7.1–7.8 (m, 11H, Ar-H, C6-H and NH, D2O exchangeable), 8.2 (s, 1H, C2-H); IR (KBr) υ (cm−1): 3440, 3330 (NH2) 3260 (NH), 1705 (C=O), 1600 (C=C), 1580 (C=N); MS (EI)m/z: 411 (M+, 28%), 412 (M+ + 1, 6.5%); Anal. Calcd for C23H21N7O (411.46): C, 67.14; H, 5.14; N, 23.83; O, 3.89%. Found: C, 67.52; H, 5.48; N, 24.15; O, 4.52%.7-Benzyl-4-hydrazinyl-2-methyl-5,6-diphenyl-7H-pyrrolo[2,3-d] pyrimidine
Vf. Yield: 67%; M.P. 147–152°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.29 (s, 3H, CH3), 4.9–5.2 (brs, 2H, NH2, D2O exchangeable), 5.78 (s, 2H, Ph-CH2), 7.23–7.8 (m, 16H, Ar-H and NH, D2O exchangeable); IR (KBr) υ (cm−1): 3430, 3350 (NH2) 3250 (NH), 1605 (C=C), 1570 (C=N); MS (EI)m/z: 405 (M+, 29%), 406 (M+ + 1, 4.1%); Anal. Calcd for C26H23N5 (405.49): C, 77.01; H, 5.72; N, 17.27%. Found: C, 77.38; H, 6.05; N, 17.62%.4-(4-Hydrazinyl-2-methyl-5,6-diphenyl-7H-pyrrolo[2,3-d]pyrimidin-7-yl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one
Vg. Yield: 68%; M.P. 185–188°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.22–2.46 (s, 6H, 2*CH3), 3.11 (s, 3H, N-CH3), 4.34–4.8 (brs, 2H, NH2, D2O exchangeable), 7.2–7.8 (m, 16H, Ar-H and NH, D2O exchangeable): IR (KBr) υ (cm−1): 3420, 3350 (NH2) 3240 (NH), 1700 (C=O), 1605 (C=C), 1560 (C=N); MS (EI)m/z: 501 (M+, 31%), 502 (M++ 1, 5.4%); Anal. Calcd for C30H27N7O (501.58): C, 71.84; H, 5.43; N, 19.55; O, 3.19%. Found: C, 72.20; H, 5.81; N, 19.92; O, 3.55%.7-(3,4-Dichlorophenyl)-4-hydrazinyl-2-methyl-5,6-diphenyl-7H-pyrrolo[2,3-d]pyrimidine
Vh. Yield: 59%; M.P. 142–146 °C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.25 (s, 3H, CH3), 4.5–4.9 (brs, 2H, NH2, D2O exchangeable), 7.3–7.8 (m, 14H, Ar-H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3440, 3360 (NH2) 3250 (NH), 1610 (C=C), 1560 (C=N); MS (EI)m/z: 460 (M+, 31%), 462 (M+ + 2, 18%), 464 (M+ + 4, 4.9%); Anal. Calcd for C25H19Cl2N5 (460.36): C, 65.22; H, 4.16; Cl, 15.40; N, 15.21%. Found: C, 65.57; H, 4.52; Cl, 15.78; N, 15.56%.4-(4-Hydrazinyl-2-methyl-5-phenyl-7H-pyrrolo[2,3-d]pyrimidin-7-yl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one
Vi. Yield: 69%; M.P. 148–150°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.23–2.44 (s, 6H, 2*CH3), 3.13 (s, 3H, N-CH3), 4.4–4.78 (brs, 2H, NH2, D2O exchangeable), 7.2–7.8 (m, 12H, Ar-H, C6-H and NH, D2O exchangeable); IR (KBr) υ (cm−1): 3430, 3360 (NH2) 3250 (NH), 1705 (C=O), 1600 (C=C), 1580 (C=N); MS (EI)m/z: 501 (M+, 31%), 502 (M+ + 1, 5.4%); Anal. Calcd for C24H23N7O (425.49): C, 67.75; H, 5.45; N, 23.04; O, 3.76%. Found: C, 68.12; H, 5.76; N, 23.37; O, 4.11%.


### 2.1.15. General Procedure for the Preparation of 4-ThienopyrrolopyrimidineVI d–f (Scheme 2)

CompoundIII (0.01 mol) and thiourea (1.2 g, 0.02 mol) were refluxed in dry ethanol (20 mL) for 14 h. The reaction mixture was evaporated under reduced pressure and the residues were recrystallized from methanol to give the target compoundsVI.7-(3,4-Dichlorophenyl)-5,6-diphenyl-3H-pyrrolo[2,3-d]pyrimidine-4(7H)-thione
VId. Yield: 66%; M.P. 142–166°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 7.3–7.8 (m, 13H, Ar-H), 9.02 (s, 1H, C2-H), 11.71 (s, 1H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3250 (NH), 1630 (NH–C=S), 1560 (C=N); MS (EI)m/z: 447 (M+, 28%), 449 (M+ + 2, 18%), 451 (M++ 4, 0.98%); Anal. Calcd for C24H15Cl2N3S (447.04): C, 64.29; H, 3.37; Cl, 15.81; N, 9.37; S, 7.15%. Found: C, 64.64; H, 3.74; Cl, 16.14; N, 9.73; S, 7.52%.1,5-Dimethyl-2-phenyl-4-(5-phenyl-4-thioxo-3H-pyrrolo[2,3-d]pyrimidin-7(4H)-yl)-1H-pyrazol-3(2H)-one
VIe. Yield: 61%; M.P. 142–166°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.44 (s, 3H, CH3), 3.13 (s, 3H, N-CH3), 7.2–7.8 (m, 11H, Ar-H, and C6-H) 9.12 (s, 1H, C2-H), 12.10 (s, 1H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3230 (NH), 1700 (C=O), 1610 (NH–C=S), 1550 (C=N); MS (EI)m/z: 413 (M+, 30%), 414 (M+ + 1, 8.4%); Anal. Calcd for C23H19N5OS (413.49): C, 66.81; H, 4.63; N, 16.94; O, 3.87; S, 7.75%. Found: C, 67.16; H, 4.98; N, 17.31; O, 4.24; S, 8.12%.7-Benzyl-2-methyl-5,6-diphenyl-3H-pyrrolo[2,3-d]pyrimidine-4(7H)-thione
VIf. Yield: 47%; M.P. 165–167°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.29 (s, 3H, CH3), 5.78 (s, 2H, Ph-CH2), 7.23–7.8 (m, 16H, Ar-H and NH, D2O exchangeable); IR (KBr) υ (cm−1): 3250 (NH), 1605 (NH–C=S), 1570 (C=N); MS (EI)m/z: 407 (M+, 26%), 408 (M++ 1, 3.91%), 409 (M++ 2, 0.81%); Anal. Calcd for C26H21N3S (407.53): C, 76.63; H, 5.19; N, 10.31; S, 7.87%. Found: C, 76.56; H, 5.11; N, 10.26; S, 7.80%.


### 2.1.16. General Procedure for the Preparation of Substituted Carbonohydrazonoyl DerivativesVII (Scheme 3)

A mixture ofI (0.01 mol) in concentrated HCl (10 ml) was cooled with stirring to 0–5°C under ice, and cooled sodium nitrite solution (2.5 g in 10 mL of water) was added to it dropwise during 30 minutes. The reaction mixture was then stirred for 30 minutes. Without separation, an ice-cold mixture of active methylene compounds (malononitrile and/or ethyl cyanoacetate) (0.015 mol) and sodium acetate (4.10 g; 0.05 mole) in ethanol (50 mL) were added dropwise with stirring for 15 min. The stirring was continued for 30 minutes under ice and the reaction mixture was then left for 12 h at room temperature. The precipitate was filtered off and recrystallized from ethanol/H2O to giveVII.(3-Cyano-1-(3,4-dichlorophenyl)-4,5-diphenyl-1H-pyrrol-2-yl)carbon-hydrazonoyl dicyanide
VIId. Yield: 56%; M.P. 102–106°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 6.71 (s, 1H, NH, hydrazone, D2O exchangeable), 7.3–7.8 (m, 13H, Ar-H); IR (KBr) υ (cm−1): 3290 (NH), 2320 (C≡N), 1695 (C=O), 1585 (C=N); MS (EI)m/z: 481 (M+, 19%), 482 (M+ + 2, 12.8%), 483 (M+ + 4, 2.3%); Anal. Calcd for C26H14Cl2N6 (481.33): C, 64.88; H, 2.93; Cl, 14.73; N, 17.46%. Found: C, 64.67; H, 2.78; Cl, 14.51; N, 17.12%.(3-Cyano-1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-4-phenyl-1H-pyrrol-2-yl)carbonohydrazonoyl dicyanide
VIIe. Yield: 51%; M.P. 110–114°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.42 (s, 3H, CH3), 3.11 (s, 3H, N-CH3), 6.71 (s, 1H, NH, hydrazone, D2O exchangeable), 7.2–7.8 (m, 11H, Ar-H, and C6-H); IR (KBr) υ (cm−1): 3290 (NH), 2320 (C≡N), 1695 (C=O), 1585 (C=N); MS (EI)m/z: 446 (M+, 17.8%), 447 (M+ + 1, 8.21%); Anal. Calcd for C25H18N8O (446.46): C, 67.25; H, 4.06; N, 25.10; O, 3.58%. Found: C, 67.54; H, 4.12; N, 25.23; O, 3.69%.Ethyl 2-(2-(1-Benzyl-3-cyano-4,5-diphenyl-1H-pyrrol-2-yl)hydrazono)-2-cyano-acetate
VIIf. Yield: 48%; M.P. 125–130°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 1.31 (t, 3H, J = 6.8, CH2-CH3*), 4.4 (q, 2H, J = 6.8, O-CH2), 5.62 (s, 2H, Ph-CH2), 6.8 (s, 1H, NH, hydrazone, D2O exchangeable), 7.2–7.8 (m, 15H, Ar-H, and C6-H); IR (KBr) υ (cm−1): 3290 (NH), 2320 (C≡N), 1695 (C=O), 1585 (C=N); MS (EI)m/z: 473 (M+, 18%), 474 (M+ + 1, 5.1%); Anal. Calcd for C29H23N5O2 (473.53): C, 73.56; H, 4.90; N, 14.79; O, 6.76%. Found: C, 73.48; H, 4.64; N, 14.63; O, 6.70%.


### 2.1.17. General Procedure for the Preparation of Pyrazolyl DerivativesVIII (Scheme 3)

A mixture of compoundVII (0.01 mol) and hydrazine hydrate (0.64 ml, 0.02 mole) in ethanol (30 mL) were heated under reflux for 8 h controlled by TLC. The solvent was concentrated and the reaction product was allowed to cool then pour on acidified ice/H2O. The product was filtered off, washed with water, dried, and recrystallized from ethanol to giveVIII.2-(2-(3,5-Diamino-4H-pyrazol-4-ylidene)hydrazinyl)-1-(3,4-dichloro phenyl)-4,5-diphenyl-1H-pyrrole-3-carbonitrile
VIIId. Yield: 55%; M.P. 120–124°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 6.5 (s, 4H, 2*NH2, D2O exchangeable), 7.2–8 (m, 14H, Ar-H and NH, hydrazone, D2O exchangeable); IR (KBr) υ (cm−1): 3350–3280 (broad NH and NH2), 2320 (C≡N), 1695 (C=O), 1585 (C=N); MS (EI)m/z: 513 (M+, 12%), 515 (M+ + 2, 7.8%), 516 (M+ + 4, 2.4%); Anal. Calcd for C26H17Cl2N7O (513.09): C, 60.71; H, 3.33; Cl, 13.79; N, 19.06; O, 3.11%. Found: C, 60.98; H, 3.41; Cl, 13.95; N, 19.43; O, 3.27%.2-(2-(3,5-Diamino-4H-pyrazol-4-ylidene)hydrazinyl)-1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-4-phenyl-1H-pyrrole-3-carbonitrile
VIIIe. Yield: 61%; M.P. 135–138°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.42 (s, 3H, CH3), 3.11 (s, 3H, N-CH3), 6.48 (s, 4H, 2*NH2, D2O exchangeable), 6.89 (s, 1H, NH, hydrazone, D2O exchangeable), 7.3–8 (m, 11H, Ar-H, and C6-H); IR (KBr) υ (cm−1): 3340–3290 (broad NH and NH2), 2320 (C≡N), 1695 (C=O), 1585 (C=N); MS (EI)m/z: 478 (M+, 15.2%), 479 (M+ + 1, 4.46%); Anal. Calcd for C25H22N10O (478.51): C, 62.75; H, 4.63; N, 29.27; O, 3.34%. Found: C, 62.64; H, 4.47; N, 29.02; O, 3.09%.2-(2-(3-Amino-5-hydroxy-4H-pyrazol-4-ylidene)hydrazinyl)-1-benzyl-4,5-diphenyl-1H-pyrrole-3-carbonitrile
VIIIf. Yield: 56%; M.P. 97–100°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 5.61 (s, 2H, CH2), 6.45 (s, 4H, 2*NH2, D2O exchangeable), 6.8 (s, 1H, NH, hydrazone, D2O exchangeable), 7.2–7.9 (m, 15H, Ar-H).; IR (KBr) υ (cm−1): 3340–3270 (broad NH and NH2), 2310 (C≡N), 1690 (C=O), 1575 (C=N); MS (EI)m/z: 459 (M+, 10%), 460 (M+ + 1, 2.91%); Anal. Calcd for C27H21N7O (459.50): C, 70.57; H, 4.61; N, 21.34; O, 3.48%. Found: C, 70.65; H, 4.69; N, 21.07; O, 3.41%.


## 2.1.1. 2-Amino-1-(3,4-dichlorophenyl)-4,5-diphenyl-1H-pyrrole-3-carbonitrileId (Scheme 1)

A mixture of benzoin (2 g, 0.01 mol), 3,4-dichlorophenyl amine (1.6 g, 0.01 mol) in dry benzene (50 mL), was kept at 80°C for 9 h. The reaction mixture was cooled; then malononitrile (0.66 mg, 0.01 mol) was added, followed by catalytic amount of pyridine (2 mL) portion wise and left to reflex till solid formed. The solvent was evaporated under reduced pressure and the residue was recrystallized from methanol to giveId. Yield: 45%; M.P. 118–122°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 5.21 (br.s, 2H, NH2, D2O exchangeable), 7.0–7.8 (m, 13H, Ar-H); 13C NMR (DMSO-d
6): δ 114.33, 118.24, 119.37, 125.8, 126.18, 127.80, 128.45, 129.84, 130.29, 132.16, 132.70, 133.62, 134.96, 142.05 ppm; IR (KBr) υ (cm−1): 3410, 3370 (NH2), 2220 (C≡N); MS (EI)m/z: 403 (M+, 14%), 405 (M++ 2, 8.75%), 407 (M++ 4, 1.1%); Anal. Calcd for C23H15Cl2N3 (403.06): C, 68.33; H, 3.74; Cl, 17.54; N, 10.39%. Found: C, 68.55; H, 3.92; Cl, 17.23; N, 10.72%.


## 2.1.2. 2-Amino-1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H -pyrazol-4-yl)-4-phenyl-1H -pyrrole-3-carbonitrileIe (Scheme 1)

1,5-Dimethyl-4-(2-oxo-2-phenylethylamino)-2-phenyl-1H-pyrazol-3(2H)-one [27–30](3.22 g, 0.01 mol) was dissolved in dry ethanol (20 mL); then malononitrile (0.66 g, 0.01 mol) was added, followed by sodium ethoxide (0.01 mol) portion wise, and left to reflux till solid formed. The solvent was evaporated under reduced pressure and the residue was recrystallized from methanol to giveIe.Yield: 66%; M.P. 163–166°C;1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.43 (s, 3H, CH3), 3.12 (s, 3H, N-CH3), 6.13 (br.s, 2H, NH2, D2O exchangeable), 6.8–7.8 (m, 10H, Ar-H and 1H, C6-H); IR (KBr) υ (cm−1): 3410, 3350 (NH2), 2210 (C≡N), 1703 (C=O); MS (EI)m/z: 369 (M+, 23%), 370 (M++ 1, 6.1%); Anal. Calcd for C22H19N5O (369.16): C, 71.53; H, 5.18; N, 18.96; O, 4.33%. Found: C, 71.55; H, 5.26; N, 18.70; O, 3.05%.


## 2.1.3. 2-Ethoxymethylenamino-1,5-disubstituted-4-phenyl-1H -pyrrole-3-carbonitrilesIi,j (Scheme 1)

CompoundI,d,or e (0.01 mol) in triethyl orthoformate (20 mL) was refluxed for 9 h. The solvent was removed under reduced pressure and the residue was recrystallized from methanol/water to give the target compoundsIi,j.


## 2.1.4. Ethyl N-3-Cyano-1-(3,4-dichlorophenyl)-4,5-diphenyl-1H -pyrrol-2-ylformimidateIi

Yield: 60%; M.P. 120–122°C;1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 1.30 (t, 3H,J = 7.1 Hz, CH3), 4.2 (q, 2H,J= 7.1 Hz, OCH2), 6.9–7.8 (m, 14H, Ar-H and N=CH); IR (KBr) υ (cm−1): 3070, 2900(CH), 2310(CN), 1620 (C=C), 1560 (C=N); MS (EI)m/z: 460 (M+, 13.5%), 462 (M++ 2, 8.5%), 464 (M++ 4, 2.71%); Anal. Calcd for C26H19Cl2N3O (460.35): C, 67.83; H, 4.16; Cl, 15.40; N, 9.13; O, 3.48%, Found: C, 68.03; H, 4.11; Cl, 15.63; N, 8.91; O, 3.69%.


## 2.1.5. Ethyl N-3-Cyano-1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H -pyrazol-4-yl)-4-phenyl-1H -pyrrol-2-ylacetimidateIj

Yield: 56%; M.P. 120–122°C;1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 1.20 (t, 3H,J = 7.2 Hz, CH3), 2.41 (s, 3H, CH3), 3.1 (s, 3H, N-CH3), 4.01 (q, 2H,J= 7.1 Hz, OCH2), 6.9–7.8 (m, 12H, Ar-H, C6-H and N=CH); IR (KBr) υ (cm−1): 3030, 2910(CH), 2240(CN), 1610 (C=C), 1570 (C=N); MS (EI)m/z: 425 (M+, 6.5%), 426 (M++ 1, 1.81%); Anal. Calcd for C26H23N5O2 (425.19): C, 70.57; H, 5.45; N, 16.46; O, 7.52%. Found: C, 70.21; H, 5.17; N, 16.12; O, 7.18%.


## 2.1.6. N-(4-Phenyl-1,3,5-trisubstituted-1H -pyrrol-2-yl)-acetamidesI n,o (Scheme 1)

CompoundI,d, ore (0.01 mol) in acetic anhydride (30 mL) was refluxed for 2 h, cooled, poured onto ice water, neutralized with ammonia to give a precipitate which was filtered off, dried, and recrystallized from methanol to give the target compoundsIn,o.


## 2.1.7. N-(3-Cyano-1-(3,4-dichlorophenyl)-4,5-diphenyl-1H -pyrrol-2-yl) acetamideIn

Yield: 66%; M.P. 135–138°C;1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.23 (s, 3H, CO-CH3), 7.0–7.8 (m, 13H, Ar-H), 9.5 (s, 1H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3430 (NH), 2330 (C≡N), 1710 (C=O); MS (EI)m/z: 445 (M+, 13.1%), 447 (M+ + 2, 7.9%), 449 (M+ + 4, 0.91%); Anal. Calcd for C25H17Cl2N3O (445.07): C, 67.28; H, 3.84; Cl, 15.89; N, 9.41; O, 3.58%. Found: C, 67.47; H, 4.06; Cl, 16.22; N, 9.57; O, 3.66%.


## 2.1.8. N-(3-Cyano-1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H -pyrazol-4-yl)-4-phenyl-1H -pyrrol-2-yl)acetamideIo

Yield: 72%; M.P. 135–138°C;1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.23 (s, 3H, CO-CH3), 2.43 (s, 3H, CH3), 3.12 (s, 3H, N-CH3), 7.0–7.8 (m, 11H, Ar-H and C6-H), 9.4 (s, 1H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3350 (NH), 2310 (C≡N), 1715, 1705 (C=O); MS (EI)m/z: 411 (M+, 15.4%), 412 (M++ 1, 3.73%); Anal. Calcd for C24H21N5O2 (411.17): C, 70.06; H, 5.14; N, 17.02; O, 7.78%. Found: C, 70.37; H, 5.45; N, 17.34; O, 7.95%.


## 2.1.9. 7-(2,4-Dimethyl-5-oxo-1-phenyl-2,5-dihydro-1H -pyrazol-3-yl)-5,6-diphenyl -3H-pyrrolo[2,3-d]pyrimidin-4(7H)-oneIId,e (Scheme 2)

Scheme 2
Synthetic pathways for compoundsI–VI: reagents and conditions: (1) HCO2H; (2) AcOH/HCl; (3) HCONH2; (4) NH2CSNH2; (5) POCl3; (6) N2H4·H2O; and (7) NH2CSNH2.Scheme 3
Synthetic pathways for compoundsVII–VIII: reagents and conditions: (1) NaNO2/HCl/Stirring (75 min); (2) NCCH2Y/CH3CO2NH4/EtOH; and (3) N2H4
·H2O.CompoundId ore (0.01 mol) in formic acid (20 mL, 85%) was refluxed for 12 h. The reaction mixture was cooled, poured onto ice/water to give a precipitate which was filtered, dried, and recrystallized from ethanol to give the target compoundsIId,e.7-(3,4-Dichlorophenyl)-5,6-diphenyl-3H-pyrrolo[2,3-d]pyrimidin-4(7H)-one
IId. Yield: 56%; M.P. 172–176°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 6.9–7.8 (m, 13H, Ar-H), 8.4 (s, 1H, C2-H), 12.40 (s, 1H, NH, D2O exchangeable): 13C NMR (DMSO-d
6): δ118.24, 119.37, 125.8, 126.18, 127.80, 128.45, 129.84, 130.29, 132.16, 132.70, 133.62, 134.96, 138.25, 142.05, 146.2, 163.15 ppm; IR (KBr) υ (cm−1): 3410, 3350 (NH2), 1720, 1705 (C=O), 1550(C=N); MS (EI)m/z: 432 (M+, 21.5%), 434 (M++ 2, 13.9%), 436 (M++ 4, 4.2%); Anal. Calcd for C24H15Cl2N3O (432.30): C, 66.68; H, 3.50; Cl, 16.40; N, 9.72; O, 3.70%. Found: C, 66.32; H, 3.18; Cl, 16.21; N, 9.50; O, 3.46%.7-(1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-5-phenyl-3H-pyrrolo[2,3-d]pyrimidin-4(7H)-one
IIe. Yield: 65%; M.P. 205–208°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.41 (s, 3H, CH3), 3.21 (s, 3H, N-CH3), 6.9–7.8 (m, 11H, Ar-H and C6-H), 8.32 (s, 1H, C2-H), 12.32 (s, 1H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3410, 3320 (NH2), 1720, 1680 (C=O), 1560(C=N) and disappearance of the CN group; MS (EI)m/z: 379 (M+, 23.5%), 380 (M++ 1, 7.1%); Anal. Calcd for C23H19N5O2 (379.43): C, 69.51; H, 4.82; N, 17.62; O, 8.05%. Found: C, 69.89; H, 5.16; N, 17.97; O, 8.41%.


## 2.1.10. 7-Disubstituted-2-methyl-5-phenyl-7H-pyrrolo[2,3-d]pyrimidin-4(3H)-oneIIi, j (Scheme 2)

CompoundId ore (0.01 mol) in acetic acid/HCl (3 : 1) (30 mL) was refluxed for 12 h. The reaction mixture was cooled, poured onto ice/water, neutralized with ammonia to give a precipitate which was filtered, dried, and recrystallized from methanol to give the target compoundsII i,j.7-(3,4-Dichlorophenyl)-2-methyl-5,6-diphenyl-3H-pyrrolo[2,3-d]pyrimidin-4(7H)-one
II i. Yield: 67%; M.P. 200–202°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.35 (s, 3H, C2-CH3), 6.9–7.8 (m, 13H, Ar-H), 12.40 (s, 1H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3430, 3330 (NH2), 1710 (C=O), 1570 (C=N); MS (EI)m/z: 445 (M+, 26.2%), 447 (M++ 2, 15.3%), 449 (M++ 4, 1.04%); Anal. Calcd for C25H17Cl2N3O (445.07): C, 67.28; H, 3.84; Cl, 15.89; N, 9.41; O, 3.58%. Found: C, 67.45; H, 4.11; Cl, 16.22; N, 9.74; O, 3.82%.7-(1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-2-methyl-5-phenyl-3H-pyrrolo[2,3-d]pyrimidin-4(7H)-one
II j. Yield: 67%; M.P. 225–227°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.32 (s, 3H, C2-CH3), 2.41 (s, 3H, CH3), 3.22 (s, 3H, N-CH3), 7–7.8 (m, 11H, Ar-H and C6-H), 12.36 (s, 1H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3430, 3330 (NH2), 1730, 1700 (C=O), 1560 (C=N); MS (EI)m/z: 487 (M+, 45%), 488 (M++ 1, 15.2%); Anal. Calcd for C24H21N5O2 (411.46): C, 70.06; H, 5.14; N, 17.02; O, 7.78%. Found: C, 70.24; H, 5.32; N, 17.31; O, 7.96%.


## 2.1.11.6,7-Disubstituted-5-phenyl-7H-pyrrolo[2,3-d]pyrimidin-4-ylaminesIIId, e (Scheme 2)

A suspension of the appropriate aminopyrroleI,d, ore (0.01 mol) and formamide (30 mL, 0.066 mol) were heated under reflux for 9 h, cooled, poured onto ice/water to give precipitates which were filtered off, dried, and recrystallized from ethanol to give the target compoundsIII d,e.7-(3,4-Dichlorophenyl)-5,6-diphenyl-7H-pyrrolo[2,3-d]pyrimidin-4-amine
III d. Yield: 63%; M.P. 115–118°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 5.4 (brs, 2H, NH2, D2O exchangeable), 7.1–7.7 (m, 13H, Ar-H), 8.2 (s, 1H, C2-H); IR (KBr) υ (cm−1): 3440, 3350 (NH2), 1570 (C=N), 1610 (C=C); MS (EI)m/z: 430 (M+, 31.2%), 432 (M++ 2, 17.6%), 434 (M++ 4, 0.98%); Anal. Calcd for C24H16Cl2N4 (430.08): C, 66.83; H, 3.74; Cl, 16.44; N, 12.99%. Found: C, 67.07; H, 5.11; Cl, 16.81; N, 13.36%.4-(4-Amino-5-phenyl-7H-pyrrolo[2,3-d]pyrimidin-7-yl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one
III e. Yield: 69%; M.P. 152–155°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.41 (s, 3H, CH3), 3.14 (s, 3H, N-CH3), 5.8 (brs, 2H, NH2, D2O exchangeable), 7.1–7.8 (m, 11H, Ar-H, and C6-H), 8.3 (s, 1H, C2-H); IR (KBr) υ (cm−1): 3430, 3330 (NH, NH2), 1705 (C=O), 1600 (C=C), 1540 (C=N); MS (EI)m/z: 396 (M+, 13.7%), 397 (M++ 1, 1.91%); Anal. Calcd for C23H20N6O (396.44): C, 69.68; H, 5.08; N, 21.20; O, 4.04%. Found: C, 69.42; H, 4.92; N, 20.89; O, 4.32%.


## 2.1.12. 5-(5,6-Diphenyl-4-thioxo-3H-pyrrolo[2,3-d]pyrimidin-7(4H)-yl)-1,4-dimethyl-2-phenyl-1H -pyrazol-3(2H)-oneIIIi, j (Scheme 2)

CompoundI,d, ore (0.01 mol) and thiourea (1.2 g, 0.02 mol) were refluxed in dry ethanol (20 mL) for 12 h. The reaction mixture was evaporated under reduced pressure and the residues were recrystallized from methanol to give the target compoundsIII i,j.4-Amino-7-(3,4-dichlorophenyl)-5,6-diphenyl-1H-pyrrolo[2,3-d] pyrimidine-2(7H)-thione
IIIi. Yield: 70%; M.P. 90–95°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 6.62 (s, 2H, NH2, D2O exchangeable), 7.1–7.9 (m, 13H, Ar-H), 9.22 (s, 1H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3440, 3340 (NH, NH2), 1610 (NH–C=S); MS (EI)m/z: 463 (M+, 22.36%), 465 (M++ 2, 14.23%), 467 (M+ + 4, 4.54%); Anal. Calcd for C24H16Cl2N4S (463.38): C, 62.21; H, 3.48; Cl, 15.30; N, 12.09; S, 6.92%. Found: C, 62.45; H, 3.62; Cl, 15.49; N, 12.41; S, 7.21%.4-(4-Amino-5-phenyl-2-thioxo-1H-pyrrolo[2,3-d]pyrimidin-7(2H)-yl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one
IIIj. Yield: 74%; M.P. 172–174°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.34 (s, 3H, CH3), 3.11 (s, 3H, N-CH3), 6.51 (brs, 2H, NH2, D2O exchangeable), 7.1–7.8 (m, 11H, Ar-H, and C6-H), 8.3 (s, 1H, C2-H), 8.92 (s, 1H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3440, 3370 (NH, NH2), 1610 (C=C), 1600 (NH–C=S); MS (EI)m/z: 428 (M+, 14.8%), 429 (M+ + 1, 2.31%); Anal. Calcd for C23H20N6OS (428.51): C, 64.47; H, 4.70; N, 19.61; O, 3.73; S, 7.48%. Found: C, 64.78; H, 4.97; N, 19.92; O, 3.91; S, 7.62%.


## 2.1.13. General Procedure for the Preparation of 4-ChloropyrrolopyrimidinesIVd–j (Scheme 2)

The appropriate compoundII (0.01 mol) was refluxed in phosphorus oxychloride (30 mL) for 12 h. The solution was cooled and poured with stirring onto ice/water and the formed precipitated was filtered, washed several times with water, dried, and recrystallized from ethanol to give the target compoundsIVd–j.4-Chloro-7-(3,4-dichlorophenyl)-5,6-diphenyl-7H-pyrrolo[2,3-d]pyrimidine
IVd. Yield: 76%; M.P. 124–128°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 6.9–7.8 (m, 13H, Ar-H), 8.6 (s, 1H, C2-H); 13C NMR (DMSO-d
6): δ117.5, 118.8, 126.18, 127.80, 128.45, 129.84, 130.21, 132.46, 132.64, 133.76, 134.84, 138.27, 141.05, 150.2, 151.24, 153.8 ppm; IR (KBr) υ (cm−1): 3080, 2840(CH), 1612 (C=C), 1580 (C=N); MS (EI)m/z: 449 (M+, 29.98%), 451 (M+ + 2, 23.6%), 453 (M+ + 4, 6.9%), 455 (M+ + 6, 0.66%); Anal. Calcd for C24H14Cl3N3 (449.03): C, 63.95; H, 3.13; Cl, 23.60; N, 9.32%. Found: C, 64.23; H, 3.42; Cl, 23.91; N, 9.49%.4-(4-Chloro-5-phenyl-7H-pyrrolo[2,3-d]pyrimidin-7-yl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one
IVe. Yield: 76%; M.P. 125–130°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.43 (s, 3H, CH3), 3.12 (s, 3H, N-CH3), 6.9–7.8 (m, 11H, Ar-H and C6-H), 8.5 (s, 1H, C2-H); IR (KBr) υ (cm−1): 3080, 2840 (CH), 1730 (C=O), 1612 (C=C), 1580 (C=N); MS (EI)m/z: 415 (M+, 20%), 417 (M++ 2, 5.5%); Anal. Calcd for C23H18ClN5O (415.87): C, 66.43; H, 4.36; Cl, 8.52; N, 16.84; O, 3.85%. Found: C, 66.67; H, 4.71; Cl, 8.68; N, 16.94; O, 3.99%.7-Benzyl-4-chloro-2-methyl-5,6-diphenyl-7H-pyrrolo[2,3-d]pyrimidine
IVf. Yield: 46%; M.P. 120–124°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.32 (s, 3H, CH3), 5.12 (s, 2H, Ph-CH2), 6.9–7.8 (m, 15H, Ar-H and C6-H); IR (KBr) υ (cm−1): 3080, 2840 (CH), 1610 (C=C), 1560 (C=N); MS (EI)m/z: 409 (M+, 14%), 411 (M+ + 2, 4.5%); Anal. Calcd for C26H20ClN3 (409.91): C, 76.18; H, 4.92; Cl, 8.65; N, 10.25%. Found: C, 76.47; H, 5.23; Cl, 8.96; N, 10.59%.4-(4-Chloro-2-methyl-5,6-diphenyl-7H-pyrrolo[2,3-d]pyrimidin-7-yl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one
IVg. Yield: 42%; M.P. 158–160°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.30–2.44 (s, 6H,2*CH3), 3.13 (s, 3H, N-CH3), 6.9–7.8 (m, 15H, Ar-H); IR (KBr) υ (cm−1): 3080, 2840 (CH), 1710 (C=O), 1605 (C=C), 1577 (C=N); MS (EI)m/z: 505 (M+, 13%), 507 (M+ + 2, 2.5%); Anal. Calcd for C30H24ClN5O (505.17): C, 71.21; H, 4.78; Cl, 7.01; N, 13.84; O, 3.16%. Found: C, 71.02; H, 4.97; Cl, 7.23; N, 14.06; O, 3.45%.4-Chloro-7-(3,4-dichlorophenyl)-2-methyl-5,6-diphenyl-7H-pyrrolo[2,3-d]pyrimidine
IVh. Yield: 45%; M.P. 108–110°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.36 (s, 3H, CH3), 7.2–7.8 (m, 13H, Ar-H); IR (KBr) υ (cm−1): 3080, 2840 (CH), 1600 (C=C), 1565 (C=N); MS (EI)m/z: 464 (M+, 11%), 466 (M+ + 2, 6.5%), 468 (M+ + 4, 2.3%), 394 (M+ + 6, 0.88%); Anal. Calcd for C25H16Cl3N3 (464.77): C, 64.61; H, 3.47; Cl, 22.88; N, 9.04%. Found: C, 64.99; H, 3.73; Cl, 23.08; N, 9.29%.4-(4-Chloro-2-methyl-5-phenyl-7H-pyrrolo[2,3-d]pyrimidin-7-yl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one
IVi. Yield: 42%; M.P. 95-100°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.28–2.46 (s, 6H, 2*CH3), 3.27 (s, 3H, N-CH3), 7.0–7.8 (m, 11H, Ar-H and C6-H); IR (KBr) υ (cm−1): 3070, 2850 (CH), 1700 (C=O), 1600 (C=C), 1570 (C=N); MS (EI)m/z: 429 (M+, 16%), 431 (M+ + 2, 4.7%); Anal. Calcd for C24H20ClN5O (429.90): C, 67.05; H, 4.69; Cl, 8.25; N, 16.29; O, 3.72%. Found: C, 67.42; H, 5.08; Cl, 8.57; N, 16.65; O, 4.02%.


## 2.1.14. General Procedure for the Preparation of 4-HydrazinopyrrolopyrimidinesVd–i (Scheme 2)

Method A. CompoundIV (0.01 mol) and hydrazine hydrate (8 mL, 0.015 mol, 98%) were refluxed in dry ethanol (30 mL) for 12 h. The solvent was removed under reduced pressure and the residues were recrystallized from methanol to give the target compoundsV.Method B. CompoundsIi,j (0.01 mol) in dry toluene (20 mL) and hydrazine hydrate (5 mL, 0.015 mol, 98%) were added with stirring at room temperature for 14 h. The solvent was removed under reduced pressure, and the residue was recrystallized from methanol to giveVd,e; CompoundsVd,e prepared by this method are identical in all respects (physical and spectral data) to that prepared from Method A.7-(3,4-Dichlorophenyl)-4-hydrazinyl-5,6-diphenyl-7H-pyrrolo[2,3-d]pyrimidine
Vd. Yield: (A; 68%, B; 56%); M.P. 122–126°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 4.9–5.2 (brs, 2H, NH2, D2O exchangeable), 7.1–7.8 (m, 14H, Ar-H and NH, D2O exchangeable), 8.3 (s, 1H, C2-H); 13C NMR (DMSO-d
6): δ117.45, 118.69, 126.21, 127.47, 128.4, 129.74, 130.2, 132.39, 132.64, 133.76, 134.84, 138.27, 141.05, 153.2, 153.8, 168.71 ppm; IR (KBr) υ (cm−1): 3420, 3350 (NH2) 3210 (NH), 1610 (C=C), 1580 (C=N); MS (EI)m/z: 446 (M+, 23%), 448 (M+ + 2, 14%), 450 (M+ + 4, 3.4%); Anal. Calcd for C24H17Cl2N5 (446.33): C, 64.58; H, 3.84; Cl, 15.89; N, 15.69%. Found: C, 64.95; H, 4.20; Cl, 16.23; N, 16.04%.4-(4-Hydrazinyl-5-phenyl-7H-pyrrolo[2,3-d]pyrimidin-7-yl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one
Ve. Yield: (A) 71%, (B) 60%; M.P. 142–146°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.42 (s, 3H, CH3), 3.13 (s, 3H, N-CH3), 4.8–5.1 (brs, 2H, NH2, D2O exchangeable), 7.1–7.8 (m, 11H, Ar-H, C6-H and NH, D2O exchangeable), 8.2 (s, 1H, C2-H); IR (KBr) υ (cm−1): 3440, 3330 (NH2) 3260 (NH), 1705 (C=O), 1600 (C=C), 1580 (C=N); MS (EI)m/z: 411 (M+, 28%), 412 (M+ + 1, 6.5%); Anal. Calcd for C23H21N7O (411.46): C, 67.14; H, 5.14; N, 23.83; O, 3.89%. Found: C, 67.52; H, 5.48; N, 24.15; O, 4.52%.7-Benzyl-4-hydrazinyl-2-methyl-5,6-diphenyl-7H-pyrrolo[2,3-d] pyrimidine
Vf. Yield: 67%; M.P. 147–152°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.29 (s, 3H, CH3), 4.9–5.2 (brs, 2H, NH2, D2O exchangeable), 5.78 (s, 2H, Ph-CH2), 7.23–7.8 (m, 16H, Ar-H and NH, D2O exchangeable); IR (KBr) υ (cm−1): 3430, 3350 (NH2) 3250 (NH), 1605 (C=C), 1570 (C=N); MS (EI)m/z: 405 (M+, 29%), 406 (M+ + 1, 4.1%); Anal. Calcd for C26H23N5 (405.49): C, 77.01; H, 5.72; N, 17.27%. Found: C, 77.38; H, 6.05; N, 17.62%.4-(4-Hydrazinyl-2-methyl-5,6-diphenyl-7H-pyrrolo[2,3-d]pyrimidin-7-yl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one
Vg. Yield: 68%; M.P. 185–188°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.22–2.46 (s, 6H, 2*CH3), 3.11 (s, 3H, N-CH3), 4.34–4.8 (brs, 2H, NH2, D2O exchangeable), 7.2–7.8 (m, 16H, Ar-H and NH, D2O exchangeable): IR (KBr) υ (cm−1): 3420, 3350 (NH2) 3240 (NH), 1700 (C=O), 1605 (C=C), 1560 (C=N); MS (EI)m/z: 501 (M+, 31%), 502 (M++ 1, 5.4%); Anal. Calcd for C30H27N7O (501.58): C, 71.84; H, 5.43; N, 19.55; O, 3.19%. Found: C, 72.20; H, 5.81; N, 19.92; O, 3.55%.7-(3,4-Dichlorophenyl)-4-hydrazinyl-2-methyl-5,6-diphenyl-7H-pyrrolo[2,3-d]pyrimidine
Vh. Yield: 59%; M.P. 142–146 °C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.25 (s, 3H, CH3), 4.5–4.9 (brs, 2H, NH2, D2O exchangeable), 7.3–7.8 (m, 14H, Ar-H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3440, 3360 (NH2) 3250 (NH), 1610 (C=C), 1560 (C=N); MS (EI)m/z: 460 (M+, 31%), 462 (M+ + 2, 18%), 464 (M+ + 4, 4.9%); Anal. Calcd for C25H19Cl2N5 (460.36): C, 65.22; H, 4.16; Cl, 15.40; N, 15.21%. Found: C, 65.57; H, 4.52; Cl, 15.78; N, 15.56%.4-(4-Hydrazinyl-2-methyl-5-phenyl-7H-pyrrolo[2,3-d]pyrimidin-7-yl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one
Vi. Yield: 69%; M.P. 148–150°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.23–2.44 (s, 6H, 2*CH3), 3.13 (s, 3H, N-CH3), 4.4–4.78 (brs, 2H, NH2, D2O exchangeable), 7.2–7.8 (m, 12H, Ar-H, C6-H and NH, D2O exchangeable); IR (KBr) υ (cm−1): 3430, 3360 (NH2) 3250 (NH), 1705 (C=O), 1600 (C=C), 1580 (C=N); MS (EI)m/z: 501 (M+, 31%), 502 (M+ + 1, 5.4%); Anal. Calcd for C24H23N7O (425.49): C, 67.75; H, 5.45; N, 23.04; O, 3.76%. Found: C, 68.12; H, 5.76; N, 23.37; O, 4.11%.


## 2.1.15. General Procedure for the Preparation of 4-ThienopyrrolopyrimidineVI d–f (Scheme 2)

CompoundIII (0.01 mol) and thiourea (1.2 g, 0.02 mol) were refluxed in dry ethanol (20 mL) for 14 h. The reaction mixture was evaporated under reduced pressure and the residues were recrystallized from methanol to give the target compoundsVI.7-(3,4-Dichlorophenyl)-5,6-diphenyl-3H-pyrrolo[2,3-d]pyrimidine-4(7H)-thione
VId. Yield: 66%; M.P. 142–166°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 7.3–7.8 (m, 13H, Ar-H), 9.02 (s, 1H, C2-H), 11.71 (s, 1H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3250 (NH), 1630 (NH–C=S), 1560 (C=N); MS (EI)m/z: 447 (M+, 28%), 449 (M+ + 2, 18%), 451 (M++ 4, 0.98%); Anal. Calcd for C24H15Cl2N3S (447.04): C, 64.29; H, 3.37; Cl, 15.81; N, 9.37; S, 7.15%. Found: C, 64.64; H, 3.74; Cl, 16.14; N, 9.73; S, 7.52%.1,5-Dimethyl-2-phenyl-4-(5-phenyl-4-thioxo-3H-pyrrolo[2,3-d]pyrimidin-7(4H)-yl)-1H-pyrazol-3(2H)-one
VIe. Yield: 61%; M.P. 142–166°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.44 (s, 3H, CH3), 3.13 (s, 3H, N-CH3), 7.2–7.8 (m, 11H, Ar-H, and C6-H) 9.12 (s, 1H, C2-H), 12.10 (s, 1H, NH, D2O exchangeable); IR (KBr) υ (cm−1): 3230 (NH), 1700 (C=O), 1610 (NH–C=S), 1550 (C=N); MS (EI)m/z: 413 (M+, 30%), 414 (M+ + 1, 8.4%); Anal. Calcd for C23H19N5OS (413.49): C, 66.81; H, 4.63; N, 16.94; O, 3.87; S, 7.75%. Found: C, 67.16; H, 4.98; N, 17.31; O, 4.24; S, 8.12%.7-Benzyl-2-methyl-5,6-diphenyl-3H-pyrrolo[2,3-d]pyrimidine-4(7H)-thione
VIf. Yield: 47%; M.P. 165–167°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.29 (s, 3H, CH3), 5.78 (s, 2H, Ph-CH2), 7.23–7.8 (m, 16H, Ar-H and NH, D2O exchangeable); IR (KBr) υ (cm−1): 3250 (NH), 1605 (NH–C=S), 1570 (C=N); MS (EI)m/z: 407 (M+, 26%), 408 (M++ 1, 3.91%), 409 (M++ 2, 0.81%); Anal. Calcd for C26H21N3S (407.53): C, 76.63; H, 5.19; N, 10.31; S, 7.87%. Found: C, 76.56; H, 5.11; N, 10.26; S, 7.80%.


## 2.1.16. General Procedure for the Preparation of Substituted Carbonohydrazonoyl DerivativesVII (Scheme 3)

A mixture ofI (0.01 mol) in concentrated HCl (10 ml) was cooled with stirring to 0–5°C under ice, and cooled sodium nitrite solution (2.5 g in 10 mL of water) was added to it dropwise during 30 minutes. The reaction mixture was then stirred for 30 minutes. Without separation, an ice-cold mixture of active methylene compounds (malononitrile and/or ethyl cyanoacetate) (0.015 mol) and sodium acetate (4.10 g; 0.05 mole) in ethanol (50 mL) were added dropwise with stirring for 15 min. The stirring was continued for 30 minutes under ice and the reaction mixture was then left for 12 h at room temperature. The precipitate was filtered off and recrystallized from ethanol/H2O to giveVII.(3-Cyano-1-(3,4-dichlorophenyl)-4,5-diphenyl-1H-pyrrol-2-yl)carbon-hydrazonoyl dicyanide
VIId. Yield: 56%; M.P. 102–106°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 6.71 (s, 1H, NH, hydrazone, D2O exchangeable), 7.3–7.8 (m, 13H, Ar-H); IR (KBr) υ (cm−1): 3290 (NH), 2320 (C≡N), 1695 (C=O), 1585 (C=N); MS (EI)m/z: 481 (M+, 19%), 482 (M+ + 2, 12.8%), 483 (M+ + 4, 2.3%); Anal. Calcd for C26H14Cl2N6 (481.33): C, 64.88; H, 2.93; Cl, 14.73; N, 17.46%. Found: C, 64.67; H, 2.78; Cl, 14.51; N, 17.12%.(3-Cyano-1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-4-phenyl-1H-pyrrol-2-yl)carbonohydrazonoyl dicyanide
VIIe. Yield: 51%; M.P. 110–114°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.42 (s, 3H, CH3), 3.11 (s, 3H, N-CH3), 6.71 (s, 1H, NH, hydrazone, D2O exchangeable), 7.2–7.8 (m, 11H, Ar-H, and C6-H); IR (KBr) υ (cm−1): 3290 (NH), 2320 (C≡N), 1695 (C=O), 1585 (C=N); MS (EI)m/z: 446 (M+, 17.8%), 447 (M+ + 1, 8.21%); Anal. Calcd for C25H18N8O (446.46): C, 67.25; H, 4.06; N, 25.10; O, 3.58%. Found: C, 67.54; H, 4.12; N, 25.23; O, 3.69%.Ethyl 2-(2-(1-Benzyl-3-cyano-4,5-diphenyl-1H-pyrrol-2-yl)hydrazono)-2-cyano-acetate
VIIf. Yield: 48%; M.P. 125–130°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 1.31 (t, 3H, J = 6.8, CH2-CH3*), 4.4 (q, 2H, J = 6.8, O-CH2), 5.62 (s, 2H, Ph-CH2), 6.8 (s, 1H, NH, hydrazone, D2O exchangeable), 7.2–7.8 (m, 15H, Ar-H, and C6-H); IR (KBr) υ (cm−1): 3290 (NH), 2320 (C≡N), 1695 (C=O), 1585 (C=N); MS (EI)m/z: 473 (M+, 18%), 474 (M+ + 1, 5.1%); Anal. Calcd for C29H23N5O2 (473.53): C, 73.56; H, 4.90; N, 14.79; O, 6.76%. Found: C, 73.48; H, 4.64; N, 14.63; O, 6.70%.


## 2.1.17. General Procedure for the Preparation of Pyrazolyl DerivativesVIII (Scheme 3)

A mixture of compoundVII (0.01 mol) and hydrazine hydrate (0.64 ml, 0.02 mole) in ethanol (30 mL) were heated under reflux for 8 h controlled by TLC. The solvent was concentrated and the reaction product was allowed to cool then pour on acidified ice/H2O. The product was filtered off, washed with water, dried, and recrystallized from ethanol to giveVIII.2-(2-(3,5-Diamino-4H-pyrazol-4-ylidene)hydrazinyl)-1-(3,4-dichloro phenyl)-4,5-diphenyl-1H-pyrrole-3-carbonitrile
VIIId. Yield: 55%; M.P. 120–124°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 6.5 (s, 4H, 2*NH2, D2O exchangeable), 7.2–8 (m, 14H, Ar-H and NH, hydrazone, D2O exchangeable); IR (KBr) υ (cm−1): 3350–3280 (broad NH and NH2), 2320 (C≡N), 1695 (C=O), 1585 (C=N); MS (EI)m/z: 513 (M+, 12%), 515 (M+ + 2, 7.8%), 516 (M+ + 4, 2.4%); Anal. Calcd for C26H17Cl2N7O (513.09): C, 60.71; H, 3.33; Cl, 13.79; N, 19.06; O, 3.11%. Found: C, 60.98; H, 3.41; Cl, 13.95; N, 19.43; O, 3.27%.2-(2-(3,5-Diamino-4H-pyrazol-4-ylidene)hydrazinyl)-1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-4-phenyl-1H-pyrrole-3-carbonitrile
VIIIe. Yield: 61%; M.P. 135–138°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 2.42 (s, 3H, CH3), 3.11 (s, 3H, N-CH3), 6.48 (s, 4H, 2*NH2, D2O exchangeable), 6.89 (s, 1H, NH, hydrazone, D2O exchangeable), 7.3–8 (m, 11H, Ar-H, and C6-H); IR (KBr) υ (cm−1): 3340–3290 (broad NH and NH2), 2320 (C≡N), 1695 (C=O), 1585 (C=N); MS (EI)m/z: 478 (M+, 15.2%), 479 (M+ + 1, 4.46%); Anal. Calcd for C25H22N10O (478.51): C, 62.75; H, 4.63; N, 29.27; O, 3.34%. Found: C, 62.64; H, 4.47; N, 29.02; O, 3.09%.2-(2-(3-Amino-5-hydroxy-4H-pyrazol-4-ylidene)hydrazinyl)-1-benzyl-4,5-diphenyl-1H-pyrrole-3-carbonitrile
VIIIf. Yield: 56%; M.P. 97–100°C; 1H NMR (DMSO-d
6, 300 MHz) δ (ppm): 5.61 (s, 2H, CH2), 6.45 (s, 4H, 2*NH2, D2O exchangeable), 6.8 (s, 1H, NH, hydrazone, D2O exchangeable), 7.2–7.9 (m, 15H, Ar-H).; IR (KBr) υ (cm−1): 3340–3270 (broad NH and NH2), 2310 (C≡N), 1690 (C=O), 1575 (C=N); MS (EI)m/z: 459 (M+, 10%), 460 (M+ + 1, 2.91%); Anal. Calcd for C27H21N7O (459.50): C, 70.57; H, 4.61; N, 21.34; O, 3.48%. Found: C, 70.65; H, 4.69; N, 21.07; O, 3.41%.


## 3. Biological Screening

### 3.1. Animals

The complete course of the experiment was conducted using male Wistar albino rats (200–250 g), reared and maintained in the animal house of the institution and provided free access to pelleted food and waterad libitum. The rats were maintained in a controlled environment (12 h light and dark cycle) for about a week for acclimatization. The protocol of the study was approved by the animal ethics committee of the Faculty of Pharmacy, Helwan University (10-01-2012). The study was conducted in accordance with the EC, directive 86/609/EEC for animal experiments.


### 3.2.  Dose Determination

Glimepiride (Amaryl) was used as a standard antidiabetic (4 mg/kg) in 1% gum acacia and administered orally [32]. Equivalent doses of all derivatives were calculated according to their molecular weight [M·wt].


### 3.3. Sucrose-Loaded Model (SLM)

Male Wistar rats were fasted overnight. Blood was collected initially and then the compounds were given to corresponding groups consisting of six rats each by oral gavage. A sucrose load of (10 gm/kg) body weight was given to each rat after half an hour posttest treatment. Blood was collected in 30, 60, 90, and 120 min after sucrose load [33]. The percentages (%) fallen in blood glucose level were calculated according to the AUC method.


### 3.4. Toxicity Study

The derivatives, which showed antihyperglycemic activity in this study, were subjected toin vivo acute toxicity study by testing their effect on serum liver and kidney markers.


### 3.5. Induction of Experimental Diabetes

Diabetes was induced in overnight fasted rats with a single intraperitoneal injection of streptozotocin (STZ) (Sigma-Aldrich, Co., St. Louis, USA. Catalog number: 1001062761) in a dose of 65 mg/kg. STZ was freshly dissolved in ice cold citrate buffer (0.01 M, pH 4.5) prior to injection [34]. After 48 h, rats showing blood glucose level  ≥ 200 mg/dl were included in the experiment [35].


### 3.6.  Experimental Design

Seventy-six rats (fourteen groups of 5-6 rats each) were used to investigate the antihyperglycemic effect of 12 pyrrole and pyrrolo pyrimidine derivatives.Group1 was diabetic control;Group2, diabetic + Glimepiride (Amaryl) (4 mg/kg), served as a reference antidiabetic drug.Groups(3–14) were given the various pyrrole derivatives (Ia–e,IVg,VIf,VIIa,b,f, andVIIIf,a, resp.). The treated groups administered the Amaryl and different derivatives orally.


### 3.7. Methodology

For each group, blood glucose was estimated at zero, one, two, four, and six hours after oral administration of derivatives using glucometer (Gluco Dr Super Sensor, AllMedicus Co., Ltd., Anyang, Gyeonggi, Korea).Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities in serum were measured according to the Reitman-Frankel calorimetric transaminase procedure [36], whereas alkaline phosphatase (ALP) was assayed by the kinetic enzymatic method by measuring the rate of hydrolysis of p-nitrophenyl phosphate by ALP according to Henry [37]; all were measured as indicators of hepatic injury. Serum creatinine levels were assayed as an indicator for renal injury in the samples by a calorimetric method [38], using commercial diagnostic kits (Diamond Diagnostics, Egypt).


### 3.8. Statistical Analysis

Data were represented as mean area under curve (AUC)± SD. Significant differences between groups was tested using GraphPad InStat (Graph software Inc., V 3.05, Ralph Stahlman, Purdue University). Appropriate graphs were plotted using Microsoft Excel 2007. P value less than 0.05 was considered statistically significant.


## 3.1. Animals

The complete course of the experiment was conducted using male Wistar albino rats (200–250 g), reared and maintained in the animal house of the institution and provided free access to pelleted food and waterad libitum. The rats were maintained in a controlled environment (12 h light and dark cycle) for about a week for acclimatization. The protocol of the study was approved by the animal ethics committee of the Faculty of Pharmacy, Helwan University (10-01-2012). The study was conducted in accordance with the EC, directive 86/609/EEC for animal experiments.


## 3.2.  Dose Determination

Glimepiride (Amaryl) was used as a standard antidiabetic (4 mg/kg) in 1% gum acacia and administered orally [32]. Equivalent doses of all derivatives were calculated according to their molecular weight [M·wt].


## 3.3. Sucrose-Loaded Model (SLM)

Male Wistar rats were fasted overnight. Blood was collected initially and then the compounds were given to corresponding groups consisting of six rats each by oral gavage. A sucrose load of (10 gm/kg) body weight was given to each rat after half an hour posttest treatment. Blood was collected in 30, 60, 90, and 120 min after sucrose load [33]. The percentages (%) fallen in blood glucose level were calculated according to the AUC method.


## 3.4. Toxicity Study

The derivatives, which showed antihyperglycemic activity in this study, were subjected toin vivo acute toxicity study by testing their effect on serum liver and kidney markers.


## 3.5. Induction of Experimental Diabetes

Diabetes was induced in overnight fasted rats with a single intraperitoneal injection of streptozotocin (STZ) (Sigma-Aldrich, Co., St. Louis, USA. Catalog number: 1001062761) in a dose of 65 mg/kg. STZ was freshly dissolved in ice cold citrate buffer (0.01 M, pH 4.5) prior to injection [34]. After 48 h, rats showing blood glucose level  ≥ 200 mg/dl were included in the experiment [35].


## 3.6.  Experimental Design

Seventy-six rats (fourteen groups of 5-6 rats each) were used to investigate the antihyperglycemic effect of 12 pyrrole and pyrrolo pyrimidine derivatives.Group1 was diabetic control;Group2, diabetic + Glimepiride (Amaryl) (4 mg/kg), served as a reference antidiabetic drug.Groups(3–14) were given the various pyrrole derivatives (Ia–e,IVg,VIf,VIIa,b,f, andVIIIf,a, resp.). The treated groups administered the Amaryl and different derivatives orally.


## 3.7. Methodology

For each group, blood glucose was estimated at zero, one, two, four, and six hours after oral administration of derivatives using glucometer (Gluco Dr Super Sensor, AllMedicus Co., Ltd., Anyang, Gyeonggi, Korea).Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities in serum were measured according to the Reitman-Frankel calorimetric transaminase procedure [36], whereas alkaline phosphatase (ALP) was assayed by the kinetic enzymatic method by measuring the rate of hydrolysis of p-nitrophenyl phosphate by ALP according to Henry [37]; all were measured as indicators of hepatic injury. Serum creatinine levels were assayed as an indicator for renal injury in the samples by a calorimetric method [38], using commercial diagnostic kits (Diamond Diagnostics, Egypt).


## 3.8. Statistical Analysis

Data were represented as mean area under curve (AUC)± SD. Significant differences between groups was tested using GraphPad InStat (Graph software Inc., V 3.05, Ralph Stahlman, Purdue University). Appropriate graphs were plotted using Microsoft Excel 2007. P value less than 0.05 was considered statistically significant.


## 4. Results and Discussion

### 4.1. Chemistry

The target pyrroleo-amino carbonitrilesIa,b, andd were prepared by the reaction [26–31] of benzoin with appropriate amines and malononitrile in nonpolar solvent. On the other hand,Ic ande were obtained by condensation of α-(arylamino)-acetophenone with malononitrile in sodium ethoxide/ethanol.CompoundsIa–e were utilized for the preparation of pyrrole derivativesIf–o using appropriate reagents and reaction conditions; heatingIa–e with triethyl orthoformate (TEOF) afforded the corresponding 2-ethoxy methylamino derivativeIf–j, while, on react with acetic anhydride, the corresponding 2-acetylaminoIk–o were afforded, as revealed in Scheme 1.On the other hand, the pyrrole derivativesIa–e were converted to the corresponding pyrrolo[2,3-d]pyrimidine-4-onesIIa–j via condensation with formic acid [39, 40] and/or AcOH/HCl [28, 41], as revealed in Scheme 2.Interaction [41] ofIa–e with formamide afforded the corresponding 4-amino pyrrolo[2,3-d]pyrimidinesIIIa–e, which can also be prepared via stirring of the imidateI f–j with ammonium hydroxide at room temperature, as revealed in Scheme 2. The reaction of pyrroleo-amino carbonitrilesIa–e with thiourea in ethanol was reported [42] to afford the corresponding 4-aminopyrimidine-2-thioneIIIf–j.PyrrolopyrimidinonesIIa–j were converted [41, 43, 44] to its corresponding 4-chloro derivativeIVa–j by refluxing with phosphorus oxychloride, as revealed in Scheme 2.The 4-chloroIVa–j were utilized for the preparation of pyrrolopyrimidine derivativesVa–j andVIa–j using appropriate reagents and reaction conditions [40, 44]: the synthesis of certain 4-hydrazino-7H-pyrrolo[2,3-d]pyrimidinesVa–j by hydrazinolysis of the corresponding 4-chloro analogues. Yet, when 4-chloro analoguesIVa–j and thiourea were heated [45] in absolute ethanol, the pyrrolopyrimidine-4(3H)-thionesVIa–f were obtained, as revealed in Scheme 2
. Diazotisation reaction of amino group in 2-amino-pyrrole, followed by coupling of the diazonium salt with active methylenes (ex: malononitrile) has been reported [46–48].Diazotization ofIa–e using a mixture of sodium nitrite and HCl (without acetic acid) at 0–5°C, without separation, adding an active methylene compounds, namely, malononitrile and/or ethyl cyanoacetate in ethanol in the presence of sodium acetate afforded the corresponding hydrazono derivativesVIIa–i. This reaction could be explained via formation of the diazonium chlorides at first, which in addition to malononitrile affordedVIIa–i. Cyclization of hydrazono derivatives 2 using hydrazine hydrate in boiling ethanol leads to the formation of the corresponding pyrazolin-5-one derivativesVIIIa–i, as revealed in Scheme 3.


### 4.2. Biological Activities

Twelve of the synthesized Pyrroles and pyrrolopyrimidines were evaluated for their antihyperglycemic activity using both streptozotocin models of diabetes and sucrose load model [32–35]. The synthesized compounds were assessed for their antihyperglycemic activity, which is comparable to Glimepiride (Amaryl) the standard antihyperglycemic drug, by comparing the mean area under the curve (AUC) for the blood glucose level between the different studied groups. The proved pyrrole derivatives, which showed promising decrease in the serum blood glucose level, were subjected to test their toxicityin vivo on serum liver and kidney markers.The tested compounds were classified into 2 main groups: first, the open form pyrrole derivatives, namely,Ia–e (pyrroleo-amino carbonitriles), hydrazone derivativesVIIa,b, andf, and pyrazolin-5-one derivativesVIIIa,f;second, the pyrrolopyrimidines, namely, 4-chloroIVg and 4-thio derivativesVIf.Only the open form pyrrole derivatives, namely,I a,c, ande (pyrroleo-amino carbonitriles), induced a significant decrease in blood glucose level in the sucrose load model (17.4%, 18%, and 16.7%, respectively) compared to the untreated normal control. Moreover, they induced significant decrease in blood glucose level in the STZ model of diabetes (33.3%, 35.3%, and 29.5%, respectively) compared to the diabetic control group, as depicted in Table 1.Table 1
Effect of various treatments on the mean area under curve (AUC) of blood glucose levels in rats.
Testedcompound(s)
% reduction in blood glucose compared to control
SLM
STZ
Amaryl
[Standard drug]
27.7
a
30.4
a
[
Ia
]
17.4
a
33.3
a
[
Ib
]
10.9
a
NA
[
Ic
]
18
a
35.3
a
[
Id
]
NA
NA
[
Ie
]
16.7
a
29.5
a
[
IVg
]
13
a
11.2
a
[
VIf
]
NA
NA
[
VIIa
]
NA
NA
[
VIIb
]
NA
NA
[
VIIf
]
NA
NA
[
VIIIa
]
NA
NA
[
VIIIf
]
NA
NA
NA = not active.
aConsidered significant compared to control (P
≤
0.05).
SLM: Sucrose-Loaded Model; STZ: Streptozotocin model of diabetes.Comparing the antihyperglycemic activity of the these compounds with that of the reference antidiabetic drug (Amaryl) showed that compoundsIa,Ic, andIe showed significant decrease in the blood glucose level (109.4%, 116.2%, and 97%, respectively) when compared to the activity of Amaryl, as shown in Figure 3.Figure 3
Potency of antihyperglycemic derivatives compared to Amaryl.Among the pyrrolopyrimidines, only the 4-chloroIVg (also bearing the antipyrine moiety at N-pyrrole) showed marked but not significant decrease in blood glucose level 11.2% compared to the diabetic control group, as shown in Table 1.Studying the acute toxicity of the promising antihyperglycemic derivativesIa,c, ande on the rats showed that the levels of sera ALT, AST, ALP, and creatinine were not significantly changed from that of the control untreated group and, also, the rats did not die or show any toxicity symptoms, as shown in Table 2.Table 2
Effect of compoundsIa, Ic, and Ie on ALT, AST, ALP, and creatinine.
Parameter
Control
Ia
Ic
Ie
ALT (U/L)
22.6 ± 4.6
17.9 ± 2.7
27.16 ± 6.3
20.5 ± 3.1
AST (U/L)
63.4 ± 14.6
69.4 ± 9.5
72 ± 7.8
62.7 ± 9.7
ALP (U/L)
70.6 ± 15
68.5 ± 12.3
63.8 ± 15.4
73.9 ± 13.2
Creatinine (mg/dL)
0.83 ± 0.13
0.8 ± 0.16
0.63 ± 0.09
0.77 ± 0.14To analyze structure-activity relationships, three structural components were considered: the nature of the heterocycle nucleus, the nature of the side chain of the heterocycle system, and the function of the side chain, as shown in Figure4.Pyrrole and Pyrrolopyrimidines derivatives; evaluated as antihyperglycemic agents.
(a)
(b)
(c)
(d)
(e)First, the influence of the nature of the heterocyclic system was easily observed as pyrrole (I a,c, ande) derivatives have show superior activity over pyrrolopyrimidinesIVg andVIf.Regarding the side chain function, for the pyrroles derivatives, the free amino group in pyrroleo-amino carbonitrilesI a,c, ande conferred the greater activity over the hydrazone derivativesVIIa,b, andf which showed a marked activity over the pyrazolin-5-one derivativesVIIIa,f, which have no activity. For the pyrrolopyrimidines, the 4-chloroIVg confers markedly but not significantly higher activity than the 4-thio derivativesVIf.Finally, the influence of the nature of the side chain on the heterocycle system, among the active compounds the antipyrine bearingN7-pyrrole (I e andIVg) showing a good activity over the benzyl (VIf,VIIa andVIIIa).


## 4.1. Chemistry

The target pyrroleo-amino carbonitrilesIa,b, andd were prepared by the reaction [26–31] of benzoin with appropriate amines and malononitrile in nonpolar solvent. On the other hand,Ic ande were obtained by condensation of α-(arylamino)-acetophenone with malononitrile in sodium ethoxide/ethanol.CompoundsIa–e were utilized for the preparation of pyrrole derivativesIf–o using appropriate reagents and reaction conditions; heatingIa–e with triethyl orthoformate (TEOF) afforded the corresponding 2-ethoxy methylamino derivativeIf–j, while, on react with acetic anhydride, the corresponding 2-acetylaminoIk–o were afforded, as revealed in Scheme 1.On the other hand, the pyrrole derivativesIa–e were converted to the corresponding pyrrolo[2,3-d]pyrimidine-4-onesIIa–j via condensation with formic acid [39, 40] and/or AcOH/HCl [28, 41], as revealed in Scheme 2.Interaction [41] ofIa–e with formamide afforded the corresponding 4-amino pyrrolo[2,3-d]pyrimidinesIIIa–e, which can also be prepared via stirring of the imidateI f–j with ammonium hydroxide at room temperature, as revealed in Scheme 2. The reaction of pyrroleo-amino carbonitrilesIa–e with thiourea in ethanol was reported [42] to afford the corresponding 4-aminopyrimidine-2-thioneIIIf–j.PyrrolopyrimidinonesIIa–j were converted [41, 43, 44] to its corresponding 4-chloro derivativeIVa–j by refluxing with phosphorus oxychloride, as revealed in Scheme 2.The 4-chloroIVa–j were utilized for the preparation of pyrrolopyrimidine derivativesVa–j andVIa–j using appropriate reagents and reaction conditions [40, 44]: the synthesis of certain 4-hydrazino-7H-pyrrolo[2,3-d]pyrimidinesVa–j by hydrazinolysis of the corresponding 4-chloro analogues. Yet, when 4-chloro analoguesIVa–j and thiourea were heated [45] in absolute ethanol, the pyrrolopyrimidine-4(3H)-thionesVIa–f were obtained, as revealed in Scheme 2
. Diazotisation reaction of amino group in 2-amino-pyrrole, followed by coupling of the diazonium salt with active methylenes (ex: malononitrile) has been reported [46–48].Diazotization ofIa–e using a mixture of sodium nitrite and HCl (without acetic acid) at 0–5°C, without separation, adding an active methylene compounds, namely, malononitrile and/or ethyl cyanoacetate in ethanol in the presence of sodium acetate afforded the corresponding hydrazono derivativesVIIa–i. This reaction could be explained via formation of the diazonium chlorides at first, which in addition to malononitrile affordedVIIa–i. Cyclization of hydrazono derivatives 2 using hydrazine hydrate in boiling ethanol leads to the formation of the corresponding pyrazolin-5-one derivativesVIIIa–i, as revealed in Scheme 3.


## 4.2. Biological Activities

Twelve of the synthesized Pyrroles and pyrrolopyrimidines were evaluated for their antihyperglycemic activity using both streptozotocin models of diabetes and sucrose load model [32–35]. The synthesized compounds were assessed for their antihyperglycemic activity, which is comparable to Glimepiride (Amaryl) the standard antihyperglycemic drug, by comparing the mean area under the curve (AUC) for the blood glucose level between the different studied groups. The proved pyrrole derivatives, which showed promising decrease in the serum blood glucose level, were subjected to test their toxicityin vivo on serum liver and kidney markers.The tested compounds were classified into 2 main groups: first, the open form pyrrole derivatives, namely,Ia–e (pyrroleo-amino carbonitriles), hydrazone derivativesVIIa,b, andf, and pyrazolin-5-one derivativesVIIIa,f;second, the pyrrolopyrimidines, namely, 4-chloroIVg and 4-thio derivativesVIf.Only the open form pyrrole derivatives, namely,I a,c, ande (pyrroleo-amino carbonitriles), induced a significant decrease in blood glucose level in the sucrose load model (17.4%, 18%, and 16.7%, respectively) compared to the untreated normal control. Moreover, they induced significant decrease in blood glucose level in the STZ model of diabetes (33.3%, 35.3%, and 29.5%, respectively) compared to the diabetic control group, as depicted in Table 1.Table 1
Effect of various treatments on the mean area under curve (AUC) of blood glucose levels in rats.
Testedcompound(s)
% reduction in blood glucose compared to control
SLM
STZ
Amaryl
[Standard drug]
27.7
a
30.4
a
[
Ia
]
17.4
a
33.3
a
[
Ib
]
10.9
a
NA
[
Ic
]
18
a
35.3
a
[
Id
]
NA
NA
[
Ie
]
16.7
a
29.5
a
[
IVg
]
13
a
11.2
a
[
VIf
]
NA
NA
[
VIIa
]
NA
NA
[
VIIb
]
NA
NA
[
VIIf
]
NA
NA
[
VIIIa
]
NA
NA
[
VIIIf
]
NA
NA
NA = not active.
aConsidered significant compared to control (P
≤
0.05).
SLM: Sucrose-Loaded Model; STZ: Streptozotocin model of diabetes.Comparing the antihyperglycemic activity of the these compounds with that of the reference antidiabetic drug (Amaryl) showed that compoundsIa,Ic, andIe showed significant decrease in the blood glucose level (109.4%, 116.2%, and 97%, respectively) when compared to the activity of Amaryl, as shown in Figure 3.Figure 3
Potency of antihyperglycemic derivatives compared to Amaryl.Among the pyrrolopyrimidines, only the 4-chloroIVg (also bearing the antipyrine moiety at N-pyrrole) showed marked but not significant decrease in blood glucose level 11.2% compared to the diabetic control group, as shown in Table 1.Studying the acute toxicity of the promising antihyperglycemic derivativesIa,c, ande on the rats showed that the levels of sera ALT, AST, ALP, and creatinine were not significantly changed from that of the control untreated group and, also, the rats did not die or show any toxicity symptoms, as shown in Table 2.Table 2
Effect of compoundsIa, Ic, and Ie on ALT, AST, ALP, and creatinine.
Parameter
Control
Ia
Ic
Ie
ALT (U/L)
22.6 ± 4.6
17.9 ± 2.7
27.16 ± 6.3
20.5 ± 3.1
AST (U/L)
63.4 ± 14.6
69.4 ± 9.5
72 ± 7.8
62.7 ± 9.7
ALP (U/L)
70.6 ± 15
68.5 ± 12.3
63.8 ± 15.4
73.9 ± 13.2
Creatinine (mg/dL)
0.83 ± 0.13
0.8 ± 0.16
0.63 ± 0.09
0.77 ± 0.14To analyze structure-activity relationships, three structural components were considered: the nature of the heterocycle nucleus, the nature of the side chain of the heterocycle system, and the function of the side chain, as shown in Figure4.Pyrrole and Pyrrolopyrimidines derivatives; evaluated as antihyperglycemic agents.
(a)
(b)
(c)
(d)
(e)First, the influence of the nature of the heterocyclic system was easily observed as pyrrole (I a,c, ande) derivatives have show superior activity over pyrrolopyrimidinesIVg andVIf.Regarding the side chain function, for the pyrroles derivatives, the free amino group in pyrroleo-amino carbonitrilesI a,c, ande conferred the greater activity over the hydrazone derivativesVIIa,b, andf which showed a marked activity over the pyrazolin-5-one derivativesVIIIa,f, which have no activity. For the pyrrolopyrimidines, the 4-chloroIVg confers markedly but not significantly higher activity than the 4-thio derivativesVIf.Finally, the influence of the nature of the side chain on the heterocycle system, among the active compounds the antipyrine bearingN7-pyrrole (I e andIVg) showing a good activity over the benzyl (VIf,VIIa andVIIIa).


## 5. Conclusion

In the present study, we described a straightforward and efficient synthesis of some pyrroles and pyrrolo[2,3-d]pyrimidine and also,we examined their effects as antihperglycemic agents. The structure-activity relationship (SAR) results indicated that the pyrrolesIa,c, ande containing amino and cyano groups displayed good to moderate antihyperglycemic activity profile compared to control. On diazotization of the amino group inVII andVIII, this did not enhance the activity. The introduction of chloro group toIVg resulted in an enhanced antihyperglycemic activity of the pyrrolopyrimidine analogs over the hydrazine derivatives. These results and others demonstrated that the synthesized pyrrole and pyrrolopyrimidine compounds are promising antihyperglycemic agents.



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*Source: 249780-2014-06-26.xml*