Abstract:
Novel quinazoline inhibitors of endothelin converting enzyme are described, as well as methods for the preparation and pharmaceutical compositions of the same, which are useful in treating elevated levels of endothelin and in controlling hypertension, myocardial infarction and ischemia, metabolic, endocrinological, and neurological disorders, congestive heart failure, endotoxic and hemorrhagic shock, septic shock, subarachnoid hemorrhage, arrhythmias, asthma, acute and chronic renal failure, cyclosporin-A induced nephrotoxicity, angina, gastric mucosal damage, ischemic bowel disease, cancer, pulmonary hypertension, preeclampsia, atherosclerotic disorders including Raynaud&#39;s disease and restenosis, cerebral ischemia and vasospasm, and diabetes.

Description:
BACKGROUND OF THE INVENTION 
     This application is a divisional application of U.S. Ser. No. 08/363,104, filed Dec. 22, 1994, now U.S. Pat. No. 5,658,902. 
    
    
     The present invention relates to novel quinazoline inhibitors of endothelin converting enzyme useful as pharmaceutical agents, to methods for their production, to pharmaceutical compositions which include these compounds and a pharmaceutically acceptable carrier, and to pharmaceutical methods of treatment. More particularly, the novel compounds of the present invention are inhibitors of endothelin converting enzyme useful in treating elevated levels of endothelin and in controlling hypertension, myocardial infarction and ischemia, metabolic, endocrinological, and neurological disorders, congestive heart failure, endotoxic and hemorrhagic shock, septic shock, subarachnoid hemorrhage, arrhythmias, asthma, acute and chronic renal failure, cyclosporin-A induced nephrotoxicity, angina, gastric mucosal damage, ischemic bowel disease, cancer, pulmonary hypertension, preeclampsia, atherosclerotic disorders including Raynaud&#39;s disease and restenosis, cerebral ischemia and vasospasm, and diabetes. 
     Endothelin-1 (ET-1), a potent vasoconstrictor, is a 21 amino acid bicyclic peptide that was first isolated from cultured porcine aortic endothelial cells. Endothelin-1, is one of a family of structurally similar bicyclic peptides which include; ET-2, ET-3, vasoactive intestinal contractor (VIC), and the sarafotoxins (SRTXs). The unique bicyclic structure and corresponding arrangement of the disulfide bridges of ET-1, which are the same for the endothelins, VIC, and the sarafotoxins, has led to significant speculation as to the importance of the resulting induced secondary structure to receptor binding and functional activity. ET-1 analogs with incorrect disulfide pairings exhibit at least 100-fold less vasoconstrictor activity. 
     Endothelin-1 is generated from a 203 amino acid peptide known as preproendothelin by an unknown dibasic endopeptidase. This enzyme cleaves the prepropeptide to a 38 (human) or 39 (porcine) amino acid peptide known as big endothelin or proendothelin. Big ET is then cleaved by an enzyme, known as endothelin converting enzyme or ECE, to afford the biologically active molecule ET-1. Big ET is only 1% as potent as ET-1 in inducing contractile activity in vascular strips but it is equally potent in vivo at raising blood pressure, presumably by rapid conversion to ET-1 (Kimura S, Kasuya Y, Sawamura T, et al., &#34;Conversion of big endothelin-1 to 21-residue endothelin-1 is essential for expression of full vasoconstrictor activity: Structure-activity relationship of big endothelin-1,&#34; J Cardiovasc Pharmacol 1989;13:S5). There have been numerous reports describing possible proteases in both the cytoplasm and membrane bound cellular fractions of endothelial cells (Ikegawa R, Matsumura Y, Takaoka M, et al., &#34;Evidence for pepstatin-sensitive conversion of porcine big endothelin-1 to endothelin-1 by the endothelial cell extract,&#34; Biochem Biophys Res Commun 1990;167:860; Sawamura T, Kimura S, Shinmi O, et al., &#34;Characterization of endothelin converting enzyme activities in soluble fraction of bovine cultured endothelial cells,&#34; Biochem Biophys Res Commun 1990;169:1138; Sawamura T, Shinmi O, Kishi N, et al., &#34;Analysis of big endothelin-1 digestion by cathepsin D.&#34; Biochem Biophys Res Commun 1990;172:883; Shields P P, Gonzales T A, Charles D, et al., &#34;Accumulation of pepstatin in cultured endothelial cells and its effect on endothelin processing,&#34; Biochem Biophys Res Commun 1991;177:1006; Matsumura Y, Ikegawa R, Tsukahara Y, et al., &#34;Conversion of big endothelin-1 to endothelin-1 by two types of metalloproteinases derived from porcine aortic endothelial cells,&#34; FEBS Lett, 1990;272:166; Sawamura T, Kasuya Y, Matsushita S N, et al., &#34;Phosphoramidon inhibits the intracellular conversion of big endothelin-1 to endothelin-1 in cultured endothelial cells,&#34; Biochem Biophys Res Commun 1991;174:779; Takada J, Okada K, Ikenaga T, et al., &#34;Phosphoramidon-sensitive endothelin-converting enzyme in the cytosol of cultured bovine endothelial cells,&#34; Biochem Biophys Res Commun 1991;176:860; Ahn K, Beningo K, Olds G, Hupe D, &#34;Endothelin-converting enzyme from bovine and human endothelial cells,&#34; J Vasc Res 1991;29:76, 2nd International symposium on endothelium-derived vasoactive factors). Many groups have chosen to isolate ECE from endothelial cells of various species, since endothelin is known to be synthesized and secreted by this cell type. It was initially reported that two types of protease activity were present in porcine or bovine endothelial cells that could cause conversion of big ET to ET in vitro (Ikegawa R, supra; Sawamura T, supra; Matsumura Y, supra; Takada J, supra; Ahn K, supra). However, it was subsequently found that the aspartic protease activity from porcine endothelial cells, thought to be predominantly cathepsin D, also caused further degradation of ET-1 and was therefore unlikely to be the true ECE (Sawamura T, supra). Moreover, human cathepsin D also causes rapid degradation of ET-1. In addition, there has been one study showing that the intracellular accumulation of pepstatin, an aspartic protease inhibitor, did not inhibit ET-1 production in cultured bovine aortic endothelial cells (Shields P P, supra). Stronger evidence that ECE is in fact a neutral metalloprotease has appeared (Matsumura Y, supra; Sawamura T, supra; Takada J, supra; Ahn K, supra) and, recently, rat and bovine ECE genes have been cloned and expressed, confirming that ECE is a phosphoramidon sensitive metalloprotease. (Shimada, K., Tanzawa, K., J. Biol. Chem. 1994, 269, 18275) (Dong, X., Emoto, N., Giaid, A., Slaughter, C., Kaw, S., deWit, D., Yanagisawa, M., Cell 1994, 78, 1-20). However, the nonspecific metalloproteinase inhibitor, phosphoramidon, has been shown to inhibit the intracellular conversion of big ET-1 to ET-1 in cultured vascular endothelial cells and smooth muscle cells (Sawamura T, supra). 
     ET-converting activity has been detected in both the membranous and cytosolic fractions of cultured porcine, bovine, and human endothelial cells (Matsumura Y, supra). Micromolar concentrations of phosphoramidon have been shown to block the pressor response of big ET both in vitro and in vivo (Takada J, supra; Fukuroda T, Noguchi K, Tsuchida S, et al., &#34;Inhibition of biological actions of big endothelin-1 by phosphoramidon,&#34; Biochem Biophys Res Commun 1990;172:390; Matsumura Y, Hisaki K, Takaoka M, Morimoto S, &#34;Phosphoramidon, a metalloproteinase inhibitor, suppresses the hypertensive effect of big endothelin-1,&#34; Eur J Pharmacol 1990;185:103; McMahon E G, Palomo M A, Moore W M, et al., &#34;Phosphoramidon blocks the pressor activity of porcine big endothelin-1-(1-39) in vivo and conversion of big endothelin-1-(1-39) to endothelin-1-(1-21) in vitro,&#34; Proc Natl Acad Sci USA 1991;88:703). It has recently been reported that phosphoramidon is able to inhibit vasoconstrictor effects evoked by intravenous injections of big ET-1 in anaesthetized pigs, but did not have any effect on the plasma ET-1 level (Modin A, Pernow J, Lundberg J M, &#34;Phosphoramidon inhibits the vasoconstrictor effects evoked by big endothelin-1 but not the elevation of plasma endothelin-1 in vivo,&#34; Life Sci 1991;49:1619). It should be noted that phosphoramidon is a rather general metalloproteinase inhibitor and clearly the discovery of specific ECE inhibitors such as those described in the present invention is important. 
     The importance of ECE inhibitors is supported further by more recent reports. Several studies demonstrating the inhibition of ECE by metalloprotease inhibitors like phosphoramidon in vitro have been published (Doherty, A. D., Endothelin: A New Challenge. J. Med. Chem. 1992, 35, 1493; Simonson, J. S., Endothelins: Multifunctional Renal Peptides. Physiological Reviews. 1993, 73, 375; Opgenorth, T. J.; Wu-Wong, J. R.; Shiosaki, K. Endothelin Converting Enzymes, FASEB. J. 1992, 6, 2653-2659; Pollock, D. M.; Opgenorth, T. J. Evidence for metalloprotease involvement in the in vivo effects of big endothelin-1 Am. J. Physiol. 1991, 261, 257-263). These studies have also been followed up by in vivo studies where the effects of ET in physiological conditions have been blocked by ECE inhibitors. For example, several reports have demonstrated that phosphoramidon (IC 50  =˜1 μM) inhibits ECE in vitro. These results were supported by in vivo studies where phosphoramidon blocked the vasoconstrictive effects of ET. In ganglion-blocked anesthetized rats the pressor response of big ET-1 was blocked by phosphoramidon in a dose-dependent manner (McMahon, E. G.; Palomo, M. A.; Moore, W. M. Phosphoramidon blocks the pressor activity of big endothelin (1-39) and lowers blood pressure in spontaneously hypertensive rats. J. Cardiovasc. Pharmacol. 1991, 17 (Suppl. 17), S29-S33; McMahon, E.G.; Palomo, M. A.; Moore, W. M.; McDonald, J. F.; Stern, M. K. Phosphoramidon blocks the pressor activity of porcine big endothelin-1-(1-39) in vivo and conversion of big endothelin-1-(1-39) to endothelin-1-(1-21) in vitro Proc. Natl. Acad. Sci (USA), 1991, 88, 703-707). Phosphoramidon was also shown to inhibit the effects of big ET-1 in the microvasculature of anesthetized hamsters and has also been used to suppress the lethality induced by the intravenous infusion of big ET-1 (Lawerence, E.; Brain, S. D. Big endothelin-1 and big endothelin-3 are constrictor agents in the microvasculature: evidence for the local phosphoramidon-sensitive conversion of big endothelin-1. Eur. J. Pharmacol. 1993, 233, 243-250). In all cases it was shown that phosphoramidon inhibited the effects of big ET-1 and not ET-1 indicating that it was not behaving as a receptor antagonist. Intracisternal administration of big ET-1 in anesthetized dogs decreased the caliber of the basilar artery on the angiogram and systemic arterial pressure was also elevated. These effects were blocked by phosphoramidon (Shinyama, H.; Uchida, T.; Kido, H.; Hayashi, K.; Watanabe, M.; Matsumura, Y.; Ikegawa, R.; Takaoka, M.; Morimoto, S. Phosphoramidon inhibits the conversion of intracisternally administered big endothelin-1 to endothelin-1. Biochem Biophys Res Commun 1991, 178, 24-30). Similar enzyme inhibitory activity has been reported in the studies involving phosphoramidon sensitive inhibition of hemodynamic actions of big ET-1 in rat brain (Hashim, M. A.; Tadepalli. Functional evidence for the presence of a phosphoramidon-sensitive enzyme in rat brain that converts big endothelin-1 to endothelin-1. Life Sci. 1991, 49, 207-211). 
     Endothelin is involved in many human disease states. 
     Several in vivo studies with ET antibodies have been reported in disease models. Left coronary artery ligation and reperfusion to induce myocardial infarction in the rat heart, caused a four- to sevenfold increase in endogenous endothelin levels. Administration of ET antibody was reported to reduce the size of the infarction in a dose-dependent manner (Watanabe T, et al., &#34;Endothelin in Myocardial Infarction,&#34; Nature (Lond.) 1990;344:114). Thus, ET may be involved in the pathogenesis of congestive heart failure and myocardial ischemia (Margulies K B , et al., &#34;Increased Endothelin in Experimental Heart Failure,&#34; Circulation 1990;82:2226). 
     Studies by Kon and colleagues using anti-ET antibodies in an ischemic kidney model, to deactivate endogenous ET, indicated the peptide&#39;s involvement in acute renal ischemic injury (Kon V, et al., &#34;Glomerular Actions of Endothelin In vivo,&#34; J Clin Invest 1989;83:1762). In isolated kidneys, preexposed to specific antiendothelin antibody and then challenged with cyclosporine, the renal perfusate flow and glomerular filtration rate increased, while renal resistance decreased as compared with isolated kidneys preexposed to a nonimmunized rabbit serum. The effectiveness and specificity of the anti-ET antibody were confirmed by its capacity to prevent renal deterioration caused by a single bolus dose (150 pmol) of synthetic ET, but not by infusion of angiotensin II, norepinephrine, or the thromboxane A 2  mimetic U-46619 in isolated kidneys (Perico N, et al., &#34;Endothelin Mediates the Renal Vasoconstriction Induced by Cyclosporine in the Rat,&#34; J Am Soc Nephrol 1990;1:76). 
     Others have reported inhibition of ET-1 or ET-2-induced vasoconstriction in rat isolated thoracic aorta using a monoclonal antibody to ET-1 (Koshi T, et al., &#34;Inhibition of Endothelin (ET)-1 and ET-2-Induced Vasoconstriction by Anti-ET-1 Monoclonal Antibody,&#34; Chem Pharm Bull 1991;39:1295). 
     Combined administration of ET-1 and ET-1 antibody to rabbits showed significant inhibition of the blood pressure and renal blood flow responses (Miyamori I, et al., &#34;Systemic and Regional Effects of Endothelin in Rabbits: Effects of Endothelin Antibody,&#34; Clin Exp. Pharmacol. Physiol 1990;17:691). 
     Other investigators have reported that infusion of ET-specific antibodies into spontaneously hypertensive rats (SHR) decreased mean arterial pressure (MAP), and increased glomerular filtration rate and renal blood flow. In the control study with normotensive Wistar-Kyoto rats (WKY), there were no significant changes in these parameters (Ohno A, &#34;Effects of Endothelin-Specific Antibodies and Endothelin in Spontaneously Hypertensive Rats,&#34; J Tokyo Women&#39;s Med Coll 1991;61:951). 
     In addition, elevated levels of endothelin have been reported in several disease states (see Table I below). 
     
                       TABLE I______________________________________Plasma Concentrations of Et-1 in Humans                        Et Plasma            Normal      LevelsCondition Reported            Condition   (pg/mL)______________________________________Atherosclerosis  1.4         3.1 pmol/LSurgical operation            1.5         7.3Buerger&#39;s disease            1.6         4.8Takayasu&#39;s arteries            1.6         5.3Cardiogenic shock            0.3         3.7Congestive heart failure            9.7         20.4(CHF)Mild CHF         7.1         11.1Severe CHF       7.1         13.8Dilated Cardiomyopathy            1.6         7.1Preeclampsia     10.4 pmol/L 22.6 pmol/LPulmonary hypertension            1.45        3.5Acute myocardial 1.5         3.3infarction(several reports)            6.0         11.0            0.76        4.95            0.50        3.8Subarachnoid hemorrhage            0.4         2.2Crohn&#39;s disease  0-24 Fmol/mg                        4-64 Fmol/mgUlcerative colitis            0-24 Fmol/mg                        20-50 Fmol/mgCold pressor test            1.2         8.4Raynaud&#39;s phenomenon            1.7         5.3Raynaud&#39;s/hand cooling            2.8         5.0Hemodialysis     &lt;7          10.9(several reports)            1.88        4.59Chronic renal failure            1.88        10.1Acute renal failure            1.5         10.4Uremia before    0.96        1.49hemodialysisEssential hypertension            18.5        33.9Sepsis syndrome  6.1         19.9Postoperative cardiac            6.1         11.9Inflammatory arthritides            1.5         4.2Malignant        4.3         16.2hemangioendothelioma            (after            removal)______________________________________ 
    
     Burnett and co-workers recently demonstrated that exogenous infusion of ET (2.5 ng/kg/mL) to anesthetized dogs, producing a doubling of the circulating concentration, did have biological actions (Lerman A, et al., &#34;Endothelin Has Biological Actions at Pathophysiological Concentrations,&#34; Circulation 1991;83:1808). Thus heart rate and cardiac output decreased in association with increased renal and systemic vascular resistances and antinatriuresis. These studies support a role for endothelin in the regulation of cardiovascular, renal, and endocrine function. 
     In the anesthetized dog with congestive heart failure, a significant two- to threefold elevation of circulating ET levels has been reported (Cavero P G, et al., &#34;Endothelin in Experimental Congestive Heart Failure in the Anesthetized Dog,&#34; Am J Physiol 1990;259:F312), and studies in humans have shown similar increases (Rodeheffer R J, et al., &#34;Circulating Plasma Endothelin Correlates With the Severity of Congestive Heart Failure in Humans,&#34; Am J Hypertension 1991;4:9A). When ET was chronically infused into male rats, to determine whether a long-term increase in circulating ET levels would cause a sustained elevation in mean arterial blood pressure, significant, sustained, and dose-dependent increases in mean arterial blood pressure were observed. Similar results were observed with ET-3 although larger doses were required (Mortenson L H, et al., &#34;Chronic Hypertension Produced by Infusion of Endothelin in Rats,&#34; Hypertension 1990;15:729). Recently the nonpeptide endothelin antagonist RO 46-2005 has been reported to be effective in models of acute renal ischemia and subarachnoid hemorrhage in rats (3rd International Conference on Endothelin, Houston, Tex., February 1993). In addition, the ET A  antagonist BQ-153 has also been shown to prevent early cerebral vasospasm following subarachnoid hemorrhage after intracisternal injection (Clozel M., et al., Life Sciences 1993;52:825); to prevent blood pressure increases in stroke-prone spontaneously hypertensive rats (Nishikibe M, et al., Life Sciences 1993;52:717); and to attenuate the renal vascular effects of ET-1 in anaesthetized pigs (Cirino M, et al., J Pharm Pharmacol 1992;44:782). 
     Plasma endothelin-1 levels were dramatically increased in a patient with malignant hemangio-endothelioma (Nakagawa K, et al., Nippon Hifuka Gakkai Zasshi 1990;100:1453). 
     The ET receptor antagonist BQ-123 has been shown to block ET-1-induced bronchoconstriction and tracheal smooth muscle contraction in allergic sheep providing evidence for expected efficacy in bronchopulmonary diseases such as asthma (Noguchi, et al., Am Rev Respir Dis 1992;145(4 Part 2):A858). 
     Circulating endothelin levels are elevated in women with preeclampsia and correlate closely with serum uric acid levels and measures of renal dysfunction. These observations indicate a role for ET in renal constriction in preeclampsia (Clark B A, et al., Am J Obstet Gynecol 1992;166:962). 
     Plasma inmunoreactive endothelin-1 concentrations are elevated in patients with sepsis and correlate with the degree of illness and depression of cardiac output (Pittett J, et al., Ann Surg 1991;213(3):261). 
     In addition, the ET-1 antagonist BQ-123 has been evaluated in a mouse model of endotoxic shock. This ET A  antagonist significantly increased the survival rate in this model (Toshiaki M, et al., 20.12.90. EP 0 436 189 A1). 
     Endothelin is a potent agonist in the liver eliciting both sustained vasoconstriction of the hepatic vasculature and a significant increase in hepatic glucose output (Gandhi CB, et al., J. Biol. Chem. 1990;265(29):17432). In streptozotocin-diabetic rats, there is an increased sensitivity to endothelin-1 (Tammesild P J, et al., Clin Exp Pharmacol Physiol 1992;19(4):261). In addition, increased levels of plasma ET-1 have been observed in microalbuminuric insulin-dependent diabetes mellitus patients indicating a role for ET in endocrine disorders such as diabetes (Collier A, et al., Diabetes Care 1992;15(8):1038). 
     ET A  antagonist receptor blockade has been found to produce an antihypertensive effect in normal to low renin models of hypertension with a time course similar to the inhibition of ET-1 pressor responses (Basil M K, et al., J Hypertension 1992;10(Suppl 4):S49). The endothelins have been shown to be arrhythmogenic, and to have positive chronotropic and inotropic effects, thus ET receptor blockade would be expected to be useful in arrhythmia and other cardiovascular disorders (Han S-P, et al., Life Sci 1990;46:767). 
     The widespread localization of the endothelins and their receptors in the central nervous system and cerebrovascular circulation has been described (Nikolov R K, et al., Drugs of Today 1992;28(5):303). Intracerebroventricular administration of ET-1 in rats has been shown to evoke behavioral effects. These factors strongly suggest a role for the ETs in neurological disorders. The potent vasoconstrictor action of ETs on isolated cerebral arterioles suggests the importance of these peptides in the regulation of cerebrovascular tone. Increased ET levels have been reported in some CNS disorders, i.e., in the CSF of patients with subarachnoid hemorrhage and in the plasma of women with preeclampsia. Stimulation with ET-3 under conditions of hypoglycemia have been shown to accelerate the development of striatal damage as a result of an influx of extracellular calcium. Circulating or locally produced ET has been suggested to contribute to regulation of brain fluid balance through effects on the choroid plexus and CSF production. ET-1-induced lesion development in a new model of local ischemia in the brain has been described. 
     Circulating and tissue endothelin immunoreactivity is increased more than twofold in patients with advanced atherosclerosis (Lerman A., et al., New England J Med 1991;325:997). Increased endothelin immunoreactivity has also been associated with Buerger&#39;s disease (Kanno K, et al., J Amer Med Assoc 1990;264 2868) and Raynaud&#39;s phenomenon (Zamora M R, et al., Lancet 1990;336:1144). Likewise, increased endothelin concentrations were observed in hyper-cholesterolemic rats (Horio T, et al., Atherosclerosis 1991;89:239). 
     An increase of circulating endothelin levels was observed in patients that underwent percutaneous transluminal coronary angioplasty (PTCA) (Tahara A, et al., Metab Clin Exp 1991;40:1235; Sanjay K, et al., Circulation 1991;84(Suppl. 4):726). 
     Increased plasma levels of endothelin have been measured in rats (Stelzner T J, et al., Am J Physiol 1992;262:L614) and humans (Miyauchi T, et al., Jpn J Pharmacol 1992;58:279P; Stewart DJ, et al., Ann Internal Medicine 1991;114:464) with pulmonary hypertension. 
     Elevated levels of endothelin have also been measured in patients suffering form ischemic heart disease (Yasuda M, et al., Amer Heart J 1990;119:801; Ray S G, et al., Br Heart J 1992;67:383) and either stable or unstable angina (Stewart J T, et al., Br Heart J 1991;66:7). 
     Infusion of an endothelin antibody 1 hour prior to and 1 hour after a 60-minute period of renal ischemia resulting in changes in renal function versus control. In addition, an increase in glomerular platelet-activating factor was attributed to endothelin (Lopez-Farre A, et al., J Physiology 1991;444:513-). In patients with chronic renal failure as well as in patients on regular hemodialysis treatment mean plasma endothelin levels were significantly increased (Stockenhuber F, et al., Clin Sci (Lond.) 1992;82:255). In addition, it has been suggested that the proliferative effect of endothelin on mesangial cells may be a contributing factor in chronic renal failure (Schultz P J, J Lab Clin Med 1992;119:448). 
     Also, Haleen, S., et al., FASEB J. April 1994, demonstrated efficacy of an ET A  /ET B  antagonist, PD 145065, which essentially also blocks all ET function (similar to an ECE inhibitor) in a severe model of acute renal failure. 
     The effects of endothelin receptor blockade on ischemia-induced acute renal failure and mortality were assessed in rats undergoing unilateral nephrectomy and global ischemia in the remaining kidney. Sprague Dawley male rats (300-400 g) were housed in metabolic cages for 2 days before and 7 days after renal injury; urine output and plasma creatinine levels were monitored daily. On the day of renal injury, rats were anesthetized with sodium pentobarbital (50 mg/kg, IP), heparinized (50 units, IV), and instrumented with a tail vein canulae for drug or vehicle infusion. Both kidneys were exposed via a flank incision and the right kidney was removed. The left renal artery was clamped for 60 minutes and released. PD 145065 was infused 60 minutes prior to and following the ischemic period. Renal injury was evident 1 and 2 days following ischemia from a tenfold increase in plasma creatinine levels and significant decreases in urine output. Mortality occurred primarily between the second and third days post-injury. However, mortality was significantly less (52%, N=23) in rats treated with PD 145065 compared to vehicle rats (83%, N-23). In addition, urine output on the second day following renal injury was significantly different between treatment groups on either the first or second days post-injury. Thus blockade of endothelin receptors with PD 145065 significantly decreases mortality in rats subjected to ischemia-induced renal failure. 
     Local intra-arterial administration of endothelin has been shown to induce small intestinal mucosal damage in rats in a dose-dependent manner (Mirua S, et al., Digestion 1991;48:163). Administration of endothelin-1 in the range of 50-500 pmol/kg into the left gastric artery increased the tissue type plasminogen activator release and platelet activating formation and induced gastric mucosal hemorrhagic change in a dose-dependent manner (Kurose I, et al., Gut 1992;33:868). Furthermore, it has been shown that an anti-ET-1 antibody reduced ethanol-induced vasoconstriction in a concentration-dependent manner (Masuda E, et al., Am J Physiol 1992;262:G785). Elevated endothelin levels have been observed in patients suffering from Crohn&#39;s disease and ulcerative colitis (Murch S R, et al., Lancet 1992;339:381). 
     Additionally, there is a correlation between the inhibition of ECE in an in vitro assay, as used and described for the quinazolines of the present invention, and demonstration of in vivo activity in various pathophysiological conditions. For example, Grover, G. J., et al., J. Pharmacol. Exp. Ther. 1992, 263, 1074-1082, tested the effect of phosphoramidon, an ECE inhibitor, in a rat model of ischemia. Thus, Grover, G. J., et al. determined the effect of endothelin-1 (ET-1) and big ET-1 on coronary flow and contractile function in isolated nonischemic and ischemic rat hearts. Both ET-1 (IC 50  =12 μMol) and big ET-1 (IC 50  =2 nMol) reduced coronary flow in a concentration-dependent manner. Both 30 μMol ET-1 and 10 nMol big ET-1 pretreatment significantly reduced the time to contracture in globally ischemic rat hearts, suggesting a proischemic effect. Phosphoramidon (IC 50  =100 μM) and BQ-123 (0.3 μM, ET A  receptor antagonist) abolished the preischemic increase in coronary perfusion pressure induced by big ET-1 as well as its proischemic effect. Phosphoramidon was also given IV to rats subjected to coronary occlusion and reperfusion and was found to significantly reduce infarct size 24 hour postischemia. Phosphoramidon has been disclosed to be an effective inhibitor of ECE, IC 50  =1 μM, (European Published Patent Application EP 0518299 A2 and International Published Patent Application WO 92/13944). 
     Depending on the nature of substituent(s) attached, quinazolines have been described, for example, as fungicides, insecticides, bronchodilators, hypotensive agents, analgesics and active against the trachoma virus. See, e.g., German Patents 1,800,709, 4,208,254, U.K. Patent Specification 1,199,768, U.S. Pat. Nos. 3,184,462, 3,340,260, U.K. Patent 857,362, Patterson, S. E., et al., J. Heterocycl. Chem. (1992), 29(4), 703-6, Brown, D. J., et al., Aust. J. Chem. (1985), 38(3), 467-74, Genther, C. S., et al., J. Med. Chem. (1977), 20(2), 237-43, and Russian Patent SU-466,233. Also, European Patent Publication No. 0579496A1 describes 4-aminoquinazolines having inhibitory effect on cGMP-PDE, or additionally on TXA 2  synthetase. The inhibition of cGMP-PDE is considered to be useful in diseases induced by enhancement of the metabolism of cGMP, such as hypertension, heart failure, myocardial infarction, angina, atherosclerosis, cardiac edema, pulmonary hypertension, renal insufficiency, nephrotic edema, hepatis edema, asthma, bronchitis, dementia, and immunodeficiency. The inhibition of thromboxane A 2  (TXA 2 ) synthetase is said to be useful for inflammation, hypertension, thrombosis, arteriosclerosis, cerebral apoplexy, asthma, myocardial infarction, cardiostenosis and cerebral infarction. 
     It has now been discovered that certain known and novel quinazoline derivatives possess a new property not previously reported for this class of compounds, which are inhibitors of endothelin converting enzyme. The quinazoline compounds of the present invention are thus useful in treating diseases associated with elevated levels of endothelin as mentioned above. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention is a compound of Formula I ##STR1## wherein A is N, CH or S(O) n  where n is 0, 1 or 2; 
     R is lower alkyl, halo-lower alkyl, aryl, aryl-lower alkyl, heteroaryl, or heteroraryl-lower alkyl; 
     R 1  is hydroxyalkyl containing at least 2 carbon atoms when A is N or S, lower alkoxyalkyl, thioalkyl containing at least 2 carbon atoms when A is N or S, lower alkyl thioalkyl, carboxyalkyl, an R 7  -R 8  -aminoalkyl group in which R 7  and R 8  are each independently hydrogen, or lower alkyl or when taken together with amino form a 5-7 membered saturated heterocyclic ring optionally interrupted by a second heteroatom selected from nitrogen, oxygen and sulfur, and where the heteroatom is nitrogen, said nitrogen atom may be substituted by alkyl, carboxyalkyl, or lower alkyl carboxyalkyl, and wherein said ring may be further substituted at a carbon atom by alkyl, amino, aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, carboxy, carboxyalkyl, alkylcarboxyalkyl, thio, thioalkyl, alkylthioalkyl, hydroxy, hydroxyalkyl, alkoxy, or alkoxyalkyl, wherein the alkyl portion of the R 1  groups defined above may be further substituted on the alkyl chain by aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, carboxyalkyl, alkylcarboxyalkyl, thioalkyl, alkylthioalkyl, hydroxyalkyl, or alkoxyalkyl, a 5-7 membered saturated or monounsaturated carbocyclic ring optionally fused to a benzene ring, or a 5,6 or 6,6-membered bicyclic carbocyclic rings, said rings attached directly to A or through an alkyl group, or a 5-7 membered saturated heterocyclic ring optionally fused to a benzene ring, or 5,6 or 6,6-membered heterocyclic bicyclic rings, having at least 1 heteroatom, wherein said ring is attached directly to A or through an alkyl group linking A with the ring at a carbon atom, said rings being optionally substituted by alkyl, amino, aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, carboxy, carboxyalkyl, alkylcarboxyalkyl, thio, thioalkyl, alkylthioalkyl, hydroxy, hydroxyalkyl, alkoxy, or alkoxyalkyl, OR 9  wherein R 9  is hydrogen or lower alkyl, NR 9  R 10  wherein R 9  and R 10  are each independently hydrogen, or lower alkyl, CO 2  R 9  wherein R 9  is as defined above, when A is N, a carboxy-lower alkyl side chain of a natural or unnatural α-aminoacid, or when A is S and n is zero, a hydrogen atom; 
     R 2  is absent when A is S, a hydrogen atom or lower alkyl and, when A is N, R 1  and R 2  may be combined together to form a 5- or 6-membered saturated ring optionally containing an additional nitrogen atom in the ring at the 3- or 4- position, and the additional nitrogen atom may optionally be substituted by alkyl, carboxyalkyl or lower alkyl carboxyalkyl, and the ring may be further substituted at a carbon atom by alkyl, amino, aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, carboxy, carboxyalkyl, alkylcarboxyalkyl, thio, thioalkyl, alkylthioalkyl, hydroxy, hydroxyalkyl, alkoxy, or alkoxyalkyl; 
     R 3 , R 4 , R 5  and R 6  are each independently hydrogen, halo, lower alkyl, cycloalkyl, halo-lower alkyl, lower alkoxy, hydroxyalkyl, aminoalkyl, lower alkyl aminoalkyl, di-lower alkyl aminoalkyl, nitro, cyano, SO 2  NR 11  R 12 , SO 2  R 9 , CO 2  R 9 , CONR 11  R 12 , NR 11  R 12  in which R 11  and R 12  are each independently hydrogen, lower alkyl, aryl, heteroaryl or aralkyl, or two of adjacent members R 3  to R 6  may be combined together to form a methylenedioxy group, and ethylenedioxy group or a benzene ring, or a pharmaceutically acceptable acid addition or base salt thereof; with the following provisos: 
     (a) when A is N, and R 1  is aminoalkyl, lower alkyl aminoalkyl, di-lower alkyl aminoalkyl, or hydroxyalkyl, then R 4  is iodo or R 5  is halo and R is halo-lower alkyl; 
     (b) when A is N and R 1  is a pyrrolidine optionally substituted by alkyl or carboxy-lower alkyl and R 3  and R 6  are as defined above, then R is halo-lower alkyl, aryl, aryl-lower alkyl, heteroaryl, or heteroaryl-lower alkyl, and 
     (c) when A is N, R 3  and R 6  are as defined above and R 1  and R 2  with A form a piperazine ring, then R is aryl, aryl-lower alkyl, heteroaryl or heteroaryl-lower alkyl, or when, in addition, R 4  is halo, R can be halo-lower alkyl. 
     Since elevated levels of endothelin have been shown to be involved in a number of pathophysiological states, a second aspect of the present invention is a method of treating diseases associated with elevated levels of endothelin comprising administering to a host suffering therefrom a therapeutic effective amount of an inhibitor of endothelin converting enzyme of the Formula I ##STR2## wherein A is N, CH or S(O) n  where n is 0, 1 or 2; 
     R is lower alkyl, halo-lower alkyl, aryl, aryl-lower alkyl, heteroaryl, or heteroraryl-lower alkyl; 
     R 1  is hydroxyalkyl containing at least 2 carbon atoms when A is N or S, lower alkoxyalkyl, thioalkyl containing at least 2 carbon atoms when A is N or S, lower alkyl thioalkyl, carboxyalkyl, an R 7  -R 8  -aminoalkyl group in which R 7  and R 8  are each independently hydrogen, or lower alkyl or when taken together with amino form a 5-7 membered saturated heterocyclic ring optionally interrupted by a second heteroatom selected from nitrogen, oxygen and sulfur, and where the heteroatom is nitrogen, said nitrogen atom may be substituted by alkyl, carboxyalkyl, or lower alkyl carboxyalkyl, and wherein said ring may be further substituted at a carbon atom by alkyl, amino, aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, carboxy, carboxyalkyl, alkylcarboxyalkyl, thio, thioalkyl, alkylthioalkyl, hydroxy, hydroxyalkyl, alkoxy, or alkoxyalkyl, wherein the alkyl portion of the R 1  groups defined above may be further substituted on the alkyl chain by aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, carboxyalkyl, alkylcarboxyalkyl, thioalkyl, alkylthioalkyl, hydroxyalkyl, or alkoxyalkyl, a 5-7 membered saturated or monounsaturated carbocyclic ring optionally fused to a benzene ring, or a 5,6 or 6,6-membered bicyclic carbocyclic rings, said rings attached directly to A or through an alkyl group, or a 5-7 membered saturated heterocyclic ring optionally fused to a benzene ring, or 5,6 or 6,6-membered heterocyclic bicyclic rings, having at least 1 heteroatom, wherein said ring is attached directly to A or through an alkyl group linking A with the ring at a carbon atom, said rings being optionally substituted by alkyl, amino, aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, carboxy, carboxyalkyl, alkylcarboxyalkyl, thio, thioalkyl, alkylthioalkyl, hydroxy, hydroxyalkyl, alkoxy, or alkoxyalkyl, OR 9  wherein R 9  is hydrogen or lower alkyl, NR 9  R 10  wherein R 9  and R 10  are each independently hydrogen, or lower alkyl, CO 2  R 9  wherein R 9  is as defined above, when A is N, a carboxy-lower alkyl side chain of a natural or unnatural α-aminoacid, or when A is S and n is zero, a hydrogen atom; 
     R 2  is absent when A is S, a hydrogen atom or lower alkyl and, when A is N, R 1  and R 2  may be combined together to form a 5- or 6-membered saturated ring optionally containing an additional nitrogen atom in the ring at the 3- or 4-position, and the additional nitrogen atom may optionally be substituted by alkyl, carboxyalkyl or lower alkyl carboxyalkyl, and the ring may be further substituted at a carbon atom by alkyl, amino, aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, carboxy, carboxyalkyl, alkylcarboxyalkyl, thio, thioalkyl, alkylthioalkyl, hydroxy, hydroxyalkyl, alkoxy, or alkoxyalkyl; 
     R 3 , R 4 , R 5  and R 6  are each independently hydrogen, halo, lower alkyl, cycloalkyl, halo-lower alkyl, lower alkoxy, hydroxyalkyl, aminoalkyl, lower alkyl aminoalkyl, di-lower alkyl aminoalkyl, nitro, cyano, SO 2  NR 11  R 12 , SO 2  R 9 , CO 2  R 9 , CONR 11  R 12 , NR 11  R 12  in which R 11  and R 12  are each independently hydrogen, lower alkyl, aryl, heteroaryl or aralkyl, or two of adjacent members R 3  to R 6  may be combined together to form a methylenedioxy group, and ethylenedioxy group or a benzene ring, or a pharmaceutically acceptable acid addition or base salt thereof. 
     Such diseases include acute and chronic renal failure, hypertension, myocardial infarction and myocardial ischemia, cerebral vasospasm, cirrhosis, septic shock, congestive heart failure, endotoxic shock, subarachnoid hemorrhage, arrhythmias, asthma, preeclampsia, atherosclerotic disorders including Raynaud&#39;s disease and restenosis, angina, cancer, pulmonary hypertension, ischemic disease, gastric mucosal damage, hemorrhagic shock, ischemic bowel disease, diabetes, cerebral ischemia or cerebral infarction resulting from a range of conditions such as thromboembolic or hemorrhagic stroke, cerebral vasospasm, head injury, hypoglycemia, cardiac arrest, status epilepticus, perinatal asphyxia, anoxia such as from drowning, pulmonary surgery, and cerebral trauma. 
     A third aspect of the present invention is a pharmaceutical composition for administering an effective amount of a compound of Formula I in admixture with a pharmaceutically acceptable carrier in the treatment methods mentioned above in unit dosage form. 
     DETAILED DESCRIPTION OF THE INVENTION 
     In the compounds of the present invention, the term &#34;alkyl&#34;, in general and unless specifically limited, means a straight or branched hydrocarbon radical having from 1 to 12 carbon atoms and includes, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, and the like. The term &#34;alkyl&#34; also has the same meaning when used as a suffix for &#34;aminoalkyl&#34;, &#34;hydroxyalkyl&#34;, &#34;thioalkyl&#34;, &#34;carboxyalkyl&#34; and the like. 
     The term &#34;lower&#34; preceding &#34;alkyl&#34; includes only those straight or branched hydrocarbon radicals defined above having from 1 to 7 carbon atoms. 
     The term &#34;alkoxy&#34; is O-alkyl as defined above for alkyl or lower alkyl. 
     The term &#34;aryl&#34; means an aromatic radical which is a phenyl group, a naphthyl group, a biphenyl group, a pyrenyl group, an anthracenyl group, 3,3-diphenylalanyl, 10,11-dihydro-5H-dibenzo- a,d!-(cyclohepten-5-yl)glycyl, or a fluorenyl group and the like, unsubstituted or substituted by 1 to 4 substituents selected from lower alkyl as defined above, lower alkoxy as defined above, trifluoromethyl, nitro, halogen, CN, SO 3  H, SO 2  NH 2 , SO 2  CH 3 , COOH, COO-lower alkyl, CONH 2 , CO-lower alkyl, NH 2 , NH-lower alkyl,N,N-di-lower alkyl, NH-aralkyl, N-di-aralkyl,N,N-lower alkyl-aralkyl, in which aralkyl is as defined below. 
     The term &#34;arylalkyl&#34; or &#34;aralkyl&#34; means an aromatic radical attached to an alkyl radical wherein aryl and alkyl are as defined above, for example, benzyl, fluorenylmethyl, and the like. 
     The term &#34;heteroaryl&#34; means a heteroaromatic radical which includes 2- or 3-thienyl, 2- or 3-furanyl, 2- or 3-pyrrolyl, 2-, 4-, or 5-imidazolyl, 3-, 4-, or 5-pyrazolyl, 2-, 4-, or 5-thiazolyl, 3-, 4-, or 5-isothiazolyl, 2-, 4-, or 5-oxazolyl, 3-, 4-, or 5-isoxazolyl, 3- or 5-1,2,4-triazolyl, 4- or 5-1,2,3-triazolyl, tetrazolyl, 2-, 3-, or 4-pyridinyl, 3-, 4-, or 5-pyridazinyl, 2-pyrazinyl, 2-, 4-, or 5-pyrimidinyl, 2-, 3-, 4-, 5-, 6-, 7-, or 8-quinolinyl, 1-, 3-, 4-, 5-, 6-, 7-, or 8-isoquinolinyl, 2-, 3-, 4-, 5-, 6-, or 7-indolyl, N-formyl-2-, 3-, 4-, 5-, 6-, 7-indolyl, 2-, 3-, 4-, 5-, 6-, 7-benzo b!thienyl, or 2-, 4-, 5-, 6-, or 7-benzoxazolyl, 2-, 4-, 5-, 6-, or 7-benzimidazolyl, 2-, 4-, 5-, 6-, 7-benzothiazolyl, unsubstituted or substituted by 1 to 2 substituents selected from those defined above for aryl. 
     &#34;Halogen&#34; or &#34;halo&#34; is fluorine, chlorine, bromine, or iodine. 
     A &#34;5-7 membered saturated heterocyclic ring optionally interrupted by a second heteroatom selected from nitrogen, oxygen and sulfur&#34; includes, for example, pyrrolidine, pyrrazolidine, imidazolidine, oxazolidine, thiaoxazolidine, piperidine, piperazine, morpholine, thiamorpholine, homopiperidine, and the like. When the second nitrogen atom is nitrogen as, for example, an imidazolidine or piperazine, said second nitrogen atom may be substituted by alkyl, carboxyalkyl or lower alkyl-carboxyalkyl. The carbon atoms of the above 5-7 membered heterocyclic ring may be substituted independently by alkyl, amino, aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, carboxy, carboxyalkyl, alkylcarboxyalkyl, thio, thioalkyl, alkylthioalkyl, hydroxy, hydroxyalkyl, alkoxy or alkoxyalkyl. 
     For purposes of the present invention, the above definition applies to the compounds of Formula I where R 1  is R 7  R 8  aminoalkyl and where R 7  and R 8  are taken together with the nitrogen atom. Said nitrogen atom is linked to &#34;A&#34; in Formula I. 
     A &#34;5-7 membered saturated or monounsaturated carbocyclic ring optionally fused to a benzene ring&#34; includes, for example, cyclopentane, cyclopentene, cyclohexane, cyclohexene, cycloheptane, cycloheptene, indane, tetralin and benzosuberane. 
     &#34;5,6 or 6,6-Membered bicyclic carbocyclic rings&#34; include, for example, bicyclo 3.2.1!octane or bicyclo  2.2.2!octane. 
     A &#34;5-7 membered saturated heterocyclic ring optionally fused to a benzene ring&#34; includes, for example, the &#34;5-7 membered saturated heterocyclic ring optionally interrupted by a second heteroatom selected from nitrogen, oxygen and sulfur&#34; as defined above and, in addition, dihydrobenzofuran, dihydroisobenzofuran, dihydrobenzothiophene, dihydroisobenzothiophene, indoline, isoindoline, chroman, isochroman, thiochroman, isothiochroman, tetrahydroquinoline, tetrahydroisoquinoline, and the like. 
     &#34;5,6 or 6,6-Membered heterocyclic bicyclic rings&#34; include, for example, 1-aza-bicyclo 3,2,1!octane or 1-aza-bicyclo 2.2.2!octane. 
     The above-defined carbocyclic and heterocyclic rings come under the definition of R 1  in the compounds of Formula I and, as such, are radicals where a carbon atom of said ring is attached directly to &#34;A&#34; of Formula I or through an alkyl chain linking the ring at a carbon atom with &#34;A&#34;. 
     The above-defined carbocyclic and heterocyclic rings may optionally be substituted at a ring carbon atom by alkyl, amino, aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, carboxy, carboxyalkyl, alkylcarboxyalkyl, thio, thioalkyl, alkylthioalkyl, hydroxy, hydroxyalkyl, alkoxy, or alkoxyalkyl. 
     The following table provides a representative list of natural and modified or unsaturated amino acids with abbreviations used in the present invention. 
     
         ______________________________________Abbreviation*       Amino Acid______________________________________Ala                 AlanineArg                 ArginineAsn                 AsparagineAsp                 Aspartic acidCys                 CysteineGlu                 Glutamic acidGln                 GlutamineGly                 GlycineHis                 HistidineIle                 IsoleucineLeu                 LeucineLys                 LysineMet                 MethioninePhe                 PhenylalaninePro                 ProlineSer                 SerineThr                 ThreonineTrp                 TryptophanTyr                 TyrosineVal                 Valine______________________________________ *If the optical activity of the amino acid is other than L(S), the amino acid or abbreviation is preceded by the appropriate configuration D(R) or DL(RS). 
    
     
         ______________________________________            Modified and UnnaturalAbbreviation*    Amino Acid______________________________________Nva              NorvalineNle              NorleucineAlg              2-Amino-4-pentanoic acid            (allylgycine)Cpn              2-Amino-3-cyclopropane            propanoic acid            (Cyclopropylalanine)Chx              Cyclohexylalanine            (Hexahydrophenylalanine)His(Dnp)         N.sup.im 2,4-Dinitrophenyl-his            tidineHomoPhe          2-Amino-5-phenylpentanoic            acid (homophenylalanine)1-Nal            3-(1&#39;-Naphthyl)alanine2-Nal            3-(2&#39;-Naphthyl)alaninePgy              2-Aminopentanoic acid            (Propylglycine)Pyr              2-Amino-3-(3-pyridyl)-            propanoic acid            (3-Pyridylalanine)Tza              2-Amino-3-(4-thiazolyl)-            propanoic acidTyr(Ot-Bu)       O-Tertiary butyltyrosineTyr(OMe)         O-methyltyrosineTyr(OEt)         O-ethyltyrosineTrp(For)         N.sup.in -FormyltryptophanHis(t-Bu)        N.sup.im -tertiary            butylhistidineHis(Cφ.sub.3)            N.sup.im -triphenylmethyl-histi            dine            (N.sup.im -tritylhistidine)Trp(Me)          N.sup.in -MethyltryptophanAsp(Ot-Bu)       Aspartic acid 4-tertiary            butyl esterAsp(OMe)         Aspartic acid 4-methyl            esterAsp(OBn)         Aspartic acid 4-benzyl            esterGlu(Ot-Bu)       Glutamic acid 5-tertiary            butyl esterGlu(OMe)         Glutamic acid 5-methyl            esterBta              3-Benzothienyl alanineBfa              3-Benzofuranyl alanine______________________________________ *If the optical activity of the amino acid is other than L(S), the amino acid or abbreviation is preceded by the appropriate configuration D(R) or DL(RS). 
    
     The compounds of Formula I are capable of further forming both pharmaceutically acceptable acid addition and/or base salts. All of these forms are within the scope of the present invention. 
     Pharmaceutically acceptable acid addition salts of the compounds of Formula I include salts derived from nontoxic inorganic acids such as hydrochloric, nitric, phosphoric, sulfuric, hydrobromic, hydriodic, hydrofluoric, phosphorous, and the like, as well as the salts derived from nontoxic organic acids, such as aliphatic mono- and dicarboxylic acids, phenyl-substituted alkanoic acids, hydroxy alkanoic acids, alkanedioic acids, aromatic acids, aliphatic and aromatic sulfonic acids, etc. Such salts thus include sulfate, pyrosulfate, bisulfate, sulfite, bisulfite, nitrate, phosphate, monohydrogenphosphate, dihydrogenphosphate, metaphosphate, pyrophosphate, chloride, bromide, iodide, acetate, trifluoroacetate, propionate, caprylate, isobutyrate, oxalate, malonate, succinate, suberate, sebacate, fumarate, maleate, mandelate, benzoate, chlorobenzoate, methylbenzoate, dinitrobenzoate, phthalate, benzenesulfonate, toluenesulfonate, phenylacetate, citrate, lactate, maleate, tartrate, methanesulfonate, and the like. Also contemplated are salts of amino acids such as arginate and the like and gluconate, galacturonate (see, for example, Berge S M, et al., &#34;Pharmaceutical Salts,&#34; J of Pharma Sci 1977;66:1. 
     The acid addition salts of said basic compounds are prepared by contacting the free base form with a sufficient amount of the desired acid to produce the salt in the conventional manner. Preferably, a compound of Formula I can be converted to an acidic salt by treating with an aqueous solution of the desired acid, such that the resulting pH is less than 4. The free base form may be regenerated by contacting the salt form with a base and isolating the free base in the conventional manner. The free base forms differ from their respective salt forms somewhat in certain physical properties such as solubility in polar solvents, but otherwise the salts are equivalent to their respective free base for purposes of the present invention. 
     Pharmaceutically acceptable base addition salts are formed with metals or amines, such as alkali and alkaline earth metals or organic amines. Examples of metals used as cations are sodium, potassium, magnesium, calcium, and the like. Examples of suitable amines are N,N&#39;-dibenzylethylenediamine, chloroprocaine, choline, diethanolamine, dicyclohexylamine, ethylenediamine, N-methylglucamine, and procaine (see, for example, Berge S M, et al., &#34;Pharmaceutical Salts,&#34; J of Pharma Sci, 1977;66:1. 
     The base addition salts of said acidic compounds are prepared by contacting the free acid form with a sufficient amount of the desired base to produce the salt in the conventional manner. Preferably, a compound of Formula I can be converted to a base salt by treating with an aqueous solution of the desired base, such that the resulting pH is greater than 9. The free acid form may be regenerated by contacting the salt form with an acid and isolating the free acid in the conventional manner. The free acid forms differ from their respective salt forms somewhat in certain physical properties such as solubility in polar solvents, but otherwise the salts are equivalent to their respective free acid for purposes of the present invention. 
     Certain of the compounds of the present invention can exist in unsolvated forms as well as solvated forms, including hydrated forms. In general, the solvated forms, including hydrated forms, are equivalent to unsolvated forms and are intended to be encompassed within the scope of the present invention. 
     Certain of the compounds of the present invention possess one or more chiral centers and each center may exist in the R(D) or S(L) configuration. The present invention includes all enantiomeric and epimeric forms as well as the appropriate mixtures thereof. 
     Of the above compounds of Formula I, preferred are those: 
     (1) wherein A is N; 
     (2) wherein R 1  is aminoalkyl, lower alkyl aminoalkyl, di-lower alkylaminoalkyl, hydroxyalkyl or thioalkyl, and R is halo-lower alkyl, and 
     (3) wherein R 4  is iodo and/or R 5  is halo. 
     Other preferred compounds are compounds of Formula II ##STR3## wherein R 13  and R 14  are each independently hydrogen, alkyl, aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, carboxyalkyl, alkylcarboxyalkyl, thioalkyl, alkylthioalkyl, hydroxyalkyl, or alkoxyalkyl; 
     n 1  is 0, 1, 2, or 3, and 
     R, R 2 , R 3 , R 4 , R 5 , R 6 , R 7  and R 8  are as defined above, with the proviso that when R 7  and R 8  are each independently hydrogen or lower alkyl and R 3  and R 6  are hydrogen, then R 4  is iodo or R 5  is halo and R is halo-lower alkyl. 
     Particularly valuable compounds of the Formula I are, for example, N-(6-iodo-2-trichloromethyl-quinazolin-4-yl)-ethane-1,2-diamine, N-(6-iodo-2-trichloromethyl-quinazolin-4-yl)-N-methyl-ethane-1,2-diamine, N-(6-iodo-2-trichloromethyl-quinazolin-4-yl)-N&#39;,N&#39;-dimethyl-ethane-1,2-diamine, N-(7-chloro-2-trichloromethyl-quinazolin-4-yl)-N&#39;,N&#39;-diisopropyl-ethane-1,2-diamine, (6-iodo-2-trichloromethyl-quinazolin-4-yl)-(2-piperidin-1-yl-ethyl)-amine, (6-iodo-2-trichloromethyl-quinazolin-4-yl)-(2-morpholin-4-yl-ethyl)-amine, and N&#39;-(6-iodo-2-trichloromethyl-quinazolin-4-yl)-N,N,N&#34;,N&#34;-tetramethyl-propane-1,2,3-triamine. 
     Another preferred aspect of the present invention is a compound of Formula III ##STR4## wherein A is N, CH or S(O) n  where n is 0, 1 or 2; and q is 0, 1 or 2; 
     (a) B, C, D and E are CH 2  or NR 13  in which only one of B, C, D or E is NR 13  wherein R 13  is hydrogen, lower alkyl, aralkyl, -(CH 2 ) m  CO 2  R 9  in which R 9  is hydrogen or lower alkyl, or -(CH 2 ) m  NR 9   10  in which R 9  and R 10  are each independently hydrogen or lower alkyl and m is an integer of 0 to 6, p is an integer from 0 to 2, and r is an integer from 0 to 2, or 
     (b) A is N, C, D and E are absent, p is 0 and B is NR 13  or --CH 2  NR 13  and attached to R 2  to form a 5- or 6-membered ring, in which R 13  is as defined above; 
     R is lower alkyl, halo-lower alkyl, phenyl or phenyl substituted by lower alkyl, lower alkoxy, trifluoromethyl, halo, NO 2 , CN, SO 3  H, SO 2  NH 2 , SO 2  CH 3 , COOR 9  in which R 9  is hydrogen or lower alkyl, CONR 9  R 10  wherein R 9  and R 10  are each independently hydrogen or lower alkyl, or NR 11  R 12  wherein R 11  and R 12  are each independently hydrogen, lower alkyl, aryl, heteroaryl or aralkyl, or heteroaryl; 
     R 2  is absent when A is S, a hydrogen atom or lower alkyl; 
     R 3  and R 6  are each independently hydrogen, lower alkyl or lower alkoxy, and 
     R 4  and R 5  are each independently hydrogen, lower alkyl, lower alkoxy, trifluoromethyl, halo, NO 2 , CN, SO 3  H, SO 2  NH 2 , SO 2  CH 3 , COOR 9  in which R 9  is hydrogen or lower alkyl, CONR 9  R 10  wherein R 9  and R 10  are each independently hydrogen or lower alkyl, or NR 11  R 12  wherein R 11  and R 12  are each independently hydrogen, lower alkyl, aryl, heteroaryl or aralkyl, or R 4  and R 5  may be joined together to form a methylenedioxy group or benzene ring, or a pharmaceutically acceptable acid addition or base salt thereof, with the following provisos: 
     (i) when A is N, and B, C, D and E are defined as in (a) above where p is zero and R 3  to R 6  are as defined above, then R is halo-lower alkyl, phenyl or substituted phenyl as defined above, or heteroaryl, and 
     (ii) when A is N, R 3  to R 6  are as defined above and B, C, D and E are defined as in (b) above, R is phenyl or substituted phenyl as defined above or heteroaryl, or when, in addition, R 4  is halo, R can be halo-lower alkyl. 
     Preferred compounds of Formula III are those: 
     (1) wherein A is N; 
     (2) wherein C, D and E are absent; p is 0; B is NR 13  or --CH 2  NR 13  and attached to R 2  to form a 5-or 6-membered ring; R is phenyl or phenyl substituted by lower alkyl, lower alkoxy, trifluoromethyl, halo, NO 2 , CN, SO 3  H, SO 2  NH 2 , SO 2  CH 3 , COOR 9  in which R 9  is hydrogen or lower alkyl, CONR 9  R 10  wherein R 9  and R 10  are each independently hydrogen or lower alkyl, or NR 11  R 12  wherein R 1  l and R 12  are each independently hydrogen, lower alkyl, aryl, heteroaryl or aralkyl; or, alternatively wherein R 4  is halo and R is halo-lower alkyl, e.g. 6-iodo-4-(4-methyl-piperazin-1-yl)-2-trichloromethyl-quinazoline or 6-iodo-4-piperazin-1-yl-2-trichloromethyl-quinazoline. 
     Still another preferred aspect of the present invention is a compound of Formula III, wherein 
     A is N, CH or S(O) n  where n is 0, 1 or 2; 
     B, C, D, E are CH 2  or NR 13  in which only one of B, C, D, or E is NR 13  wherein R 13  is hydrogen, lower alkyl, aralkyl, --(CH 2 ) m  CO 2  R 9  in which R 9  is hydrogen or lower alkyl, or --(CH 2 ) m  --NR 9  R 10  in which R 9  and R 10  are each independently hydrogen or lower alkyl and m is an integer of 0 to 6, and p is an integer from zero to 2; 
     R is lower alkyl, halo-lower alkyl, phenyl or phenyl substituted by lower alkyl, lower alkoxy, trifluoromethyl, halo, NO 2 , CN, SO 3  H, SO 2  NH 2 , SO 2  CH 3 , COOR 9  in which R 9  is hydrogen or lower alkyl, CONR 9  R 10  wherein R 9  and R 10  are each independently hydrogen or lower alkyl, or NR 11  R 12  wherein R 11  and R 12  are each independently hydrogen, lower alkyl, aryl, heteroaryl or aralkyl, or heteroaryl; 
     R 2  is absent when A is S, a hydrogen atom or lower alkyl; 
     R 3  and R 6  are each independently hydrogen, lower alkyl or lower alkoxy, and 
     R 4  and R 5  are each independently hydrogen, lower alkyl, lower alkoxy, trifluoromethyl, halo, NO 2 , CN, SO 3  H, SO 2  NH 2 , SO 2  CH 3 , COOR 9  in which R 9  is hydrogen or lower alkyl, CONR 9  R 10  wherein R 9  and R 10  are each independently hydrogen or lower alkyl, or NR 11  R 12  wherein R 11  and R 12  are each independently hydrogen, lower alkyl, aryl, heteroaryl or aralkyl, or R 4  and R 5  may be joined together to form a methylenedioxy group or a benzene ring, or a pharmaceutically acceptable acid addition or base salt thereof, with the proviso that when A is N and p is 0, R is halo-lower alkyl, phenyl or substituted phenyl as defined above, or heteroaryl. 
     Still another preferred embodiment is a compound of Formula III where A is N, B, D and E are CH 2 , C is N, p is 1, q is 0 and r is 2, which is (1-aza-bicyclo 2,2,2!oct-3-yl)-(6-iodo-2-trichloromethyl-quinazolin-4-yl)-amine. 
     A more preferred aspect of the present invention is a compound of Formula IV ##STR5## wherein q is 0, 1 or 2 and p is 0 or 1; R is lower alkyl, halo-lower alkyl, phenyl or phenyl substituted by lower alkyl, lower alkoxy, trifluoromethyl, halo, NO 2 , CN, SO 3  H, SO 2  NH 2 , SO 2  CH 3 , COOR 9  in which R 9  is hydrogen or lower alkyl, CONR 9  R 10  wherein R 9  and R 10  are each independently hydrogen or lower alkyl, or NR 11  R 12  wherein R 11  and R 12  are each independently hydrogen, lower alkyl, aryl, heteroaryl or aralkyl, or heteroaryl; 
     R 2  is a hydrogen atom or lower alkyl; 
     R 3  and R 6  are each independently hydrogen, lower alkyl or lower alkoxy, and 
     R 4  and R 5  are each independently hydrogen, lower alkyl, lower alkoxy, trifluoromethyl, halo, NO 2 , CN, SO 3  H, SO 2  NH 2 , SO 2  CH 3 , COOR 9  in which R 9  is hydrogen or lower alkyl, CONR 9  R 10  wherein R 9  and R 10  are each independently hydrogen or lower alkyl, or NR 11  R 12  wherein R 11  and R 12  are each independently hydrogen, lower alkyl, aryl, heteroaryl or aralkyl, or R 4  and R 5  may be joined together to form a methylenedioxy group or a benzene ring; 
     R 7  is hydrogen, lower alkyl, aralkyl, --(CH 2 ) m  CO 2  R 9  in which R 9  is hydrogen or lower alkyl, or --(CH 2 ) m  --NR 9  R 10  in which R 9  and R 10  are each independently hydrogen or lower alkyl and m is an integer of 1 to 6, or a pharmaceutically acceptable acid addition or base salt thereof; with the proviso that when p is 0, q is 1 or 2. 
     More preferred of the compounds of Formula IV are those wherein R 4  and R 5  are each independently hydrogen, trifluoromethyl, halo, NO 2 , CN, SO 3  H, SO 2  NH 2 , SO 2  CH 3 , COOR 9  in which R 9  is hydrogen or lower alkyl, or CONR 9  R 10  wherein R 9  and R 10  are each independently hydrogen or lower alkyl, and R is lower alkyl, halo-lower alkyl, phenyl or phenyl substituted by lower alkyl, lower alkoxy or halo. 
     Most preferred of the compounds of Formula IV are those wherein R 4  and R 5  are each independently hydrogen, halo or NO 2  and R is halo-lower alkyl. 
     Particularly valuable compounds of Formula III are: 
     (1-ethyl-piperidin-3-yl)-(6-iodo-2-p-tolyl-quinazolin-4-yl)-amine, 
     (1-ethyl-piperidin-3-yl)-(6-iodo-2-(4-methoxy-phenyl)-quinazolin-4-yl)-amine, 
      2-(4-chloro-phenyl)-6-iodo-quinazolin-4-yl!-(1-ethyl-piperidin-3-yl)-amine 
     (2-tert-butyl-6-iodo-quinazolin-4-yl)-(1-ethyl-piperidin-3-yl)-amine, 
     (1-ethyl-piperidin-3-yl)-(6-iodo-2-phenyl-quinazolin-4-yl)-amine, 
     (1-ethyl-piperidin-3-yl)-(6-iodo-2-trichloromethyl-quinazolin-4-yl)-amine, 
      3-(6-iodo-2-trichloromethyl-quinazolin-4-ylamino)-piperidin-1-yl!-acetic acid, 
     (1-ethyl-piperidin-3-yl)-(6-chloro-2-trichloromethyl-quinazolin-4-yl)-amine 
     (1-ethyl-piperidin-3-yl)-(6-nitro-2-trichloromethyl-quinazolin-4-yl)-amine, 
     (1-ethyl-piperidin-3-yl)-(2-trichloromethyl-quinazolin-4-yl)-amine, 
     (1-ethyl-piperidin-3-yl)-(7-chloro-2-trichloromethyl-quinazolin-4-yl)-amine 
     (1-ethyl-piperidin-3-yl)-(6-iodo-2-trifluoromethyl-quinazolin-4-yl)-amine, and 
     (1-ethyl-pyrrolidin-2-yl-methyl)-(6-iodo-2-trichloromethyl-quinazolin-4-yl)-amine. 
     The compounds of the present invention are valuable inhibitors of endothelin converting enzyme. The tests employed indicate that such compounds possess inhibitory activity towards an endothelin converting enzyme. 
     SCREENING OF ENDOTHELIN CONVERTING ENZYME (ECE) INHIBITORS 
     Cell Culture 
     A permanent human cell line (EA.hy926), derived by fusing human umbilical vein endothelial cells with the permanent human cell line A549 (derived from a human lung carcinoma), was cultured as described, except that the medium also contained HAT supplements (100 μM hypoxanthine, 0.4 μM aminopterin, 16 μM thymidine). Edgell, C.-J. S., McDonald, C. C., and Graham, J. B. (1983) Proc. Natl. Acad. Sci. USA 80, 3734-3737. Cells from passages 40 to 50 were used. Subcultures were prepared by treating confluent cells with trypsin (0.5%) and seeded either onto 24 well plates for a cell-based assay or onto roller bottles for a partial purification of the enzyme. 
     Partial Purification of ECE from EA.hy926 
     All operations were carried out at 0°-4° C. unless otherwise noted. The cells in each roller bottle were washed with phosphate-buffered saline and gently scraped. These cells were washed further with phosphate-buffered saline followed by 10 mM Tris-HCl, pH 7.5/0.25M sucrose/20 mM KCl (buffer A) and frozen immediately in liquid nitrogen. The cells from 150 roller bottles were suspended in 100 mL of buffer A containing protease inhibitors cocktail (1 mM phenylmethylsulfonyl fluoride/0.05 mM pepstatin A/0.1 mM leupeptin) and were homogenized via nitrogen cavitation (600 psi, 10 min.) and centrifuged at 5,000×g for 20 min. This process was repeated with the pellet resuspended in 100 mL of buffer A containing protease inhibitors cocktail. The combined supernatant was then centrifuged at 20,000×g for 35 min. The resulting supernatant was further centrifuged at 100,000×g for 1 h. The pellet was washed with 120 mL of 20 mM Tris-HCl, pH 7.5/0.02% NaN 3  (buffer B), resuspended in 40 mL of buffer B containing 0.5% Triton X-100 (hydrogenated) and protease inhibitors cocktail, and was stirred gently for 1 h (membrane fraction). The clear supernatant was obtained by centrifugation at 100,000×g for 1 h (detergent extract). For Ricinus communis agglutinin chromatography (RCA-I), the detergent extract was applied at a flow rate of 0.15 ml/min onto a 4-ml RCA-I column (0.5×20 cm) equilibrated with 50 mM Tris-HCl, pH 7.2/50 mM NaC1/0.02% NaN 3  /0.2% Triton X-100 (hydrogenated) (buffer C) including protease inhibitors cocktail. The column was washed with the equilibration buffer until A 280  nm of the eluate was less than 0.03, and the activity was eluted with buffer C containing 0.5M galactose at a flow rate of 0.15 ml/min. Fractions of 4 mL were collected and peak fractions were pooled (RCA-I fraction, 20 mL) (see Table II). 
     The above procedure yielded 35.6-fold purification of ECE from the membrane fraction (Table II) which was used for the screening of ECE inhibitors. This enzyme has a neutral pH optimum and is phosphoramidon-sensitive with an IC 50  value of 1.8 μM. The enzyme is also inhibited by EDTA, EGTA, and 1,10-phenanthroline but was not inhibited by pepstatin A, leupeptin, phenylmethlysulfonyl fluoride, soybean trypsin inhibitor, E-64, bestatin, captopril, enalaprilat or thiorphan. 
     The cell line, EA.hy926, contains neutral endopeptidase 24.11 (NEP 24.11) which also cleaves big ET-1 to ET-1 and c-terminal fragment (manuscript submitted). Therefore, for all ECE assays, 100 μM thiorphan or 100 nM phosphoramidon was added. Under these conditions, NEP 24.11 is completely inhibited without affecting the ECE activity. All the data were obtained in the linear range of time-course curves. 
     
                       TABLE II______________________________________Partial Purification of ECE from EA.hy926.sup.a                                 Specific                          Total  Activity  Total     Protein Concentration                          Activity                                 units/mL/Fraction  Volume mL Absorbance (280 nm)                          units.sup.b                                 A.sub.280 nm______________________________________Membrane  40.0      0.902.sup.c   382    1.1Detergent  39.4      0.387.sup.c   301    2.0extractRCA-I  20.0      0.386         275    35.6______________________________________ .sup.a ECE was partially purified from EA.hy926 grown in 150 roller bottles to confluency. .sup.b One unit of enzyme is defined as the amount generating 1 pmol of immunoreactive (ir) ET1 per min. .sup.c Absorbance shown was measured after tenfold dilution. 
    
     ECE Assay 
     The assay measured the production of ET-1 essentially as described with minor modifications. Ahn, K., Beningo, K., Olds, G., and Hupe, D. (1992) Proc. Natl. Acad. Sci. USA 89, 8606-8610. The typical reaction mixture (50 μl) contained 10 μM big ET-1, 100 mM Hepes-KOH (pH 7.0), 0.25% Triton X-100, 0.01% NaN 3 , 0.1 mM thiorphan, 0.2 mM phenylmethylsulfonyl fluoride, 0.02 mM pepstatin A, 0.1 mM leupeptin, and the enzyme. For screening inhibitors, the indicated concentration of a drug (or DMSO for control) dissolved in DMSO was added and the final concentration of DMSO was kept at 3%. After incubation for 1.5 hours at 37° C., the reaction was stopped by the addition of EDTA to give a final concentration of 10 mM. This final mixture was diluted with 60 mM KP + , pH 7.4/10 mM EDTA/8 mM NaN 3  /0.1% bovine serum albumin/0.1% Tween 20/3% DMSO (buffer D) and the generated ET-1 was measured by radioimmunoassay (RIA). 
     Radioimmunoassay (RIA) 
     ET-1 was measured by radioimmunoassay (RIA) as described previously with minor modifications. Ahn, K., Beningo, K., Olds, G., and Hupe, D. (1992) Proc. Nat. Acad. Sci. USA, 89, 8606-8610. Briefly, the RIA mixture (250 μl) contained the antibody against ET-1, an ET-1 sample, and   125  I! ET-1 (15000 cpm) in buffer D. For the analysis of ET-1 from cell based assays, the final 6% bovine serum albumin was added. The order of additions was ET-1 sample, antibody, and then   125  !ET-1. After incubation at 4° C. for 16 hr, unbound ET-1 was co-precipitated by the addition of charcoal (2.4%, wt/vol)/dextran (0.24%, wt/vol) suspension (125 μl) in 60 mM KP i  pH 7.4/10 mM EDTA/8 mM NaN 3  /0.25% gelatin (wt/vol). The amount of immunoreactive (ir) ET-1 was measured by counting the supernatant and determined from the standard curve. The cross reactivity to big ET-1 was less than 0.01% and the detection limit was 1 fmol. 
     
                       TABLE III______________________________________Biological Activity of Compounds ofthe Present Invention  Example         IC.sub.50 μM______________________________________  1       4.2 ± 0.5  2       9.2 ± 0.8  3      14.1 ± 1.5  4      29.1 ± 5.4  5      17.6 ± 1.7  6      29.6 ± 6  7      22.1 ± 4.8  8      11.1 ± 2.7  9       3.7 ± 1.6  10     25.4 ± 4.2  11     12.4 ± 1  12     11.1 ± 1.7  13      66.6 ± 11.8  14      75.5 ± 11.6  15     11.1 ± 1.7  16      8.4 ± 1.4  17      2.3 ± 0.3______________________________________ 
    
     Procedure for a cell-based assay 
     EAhy926 cells (0.2-4×10 4 ) were seeded into 24-plates and cultures as described above. At 90%-100% confluence, the cells were washed with the same media and treated with medium containing drugs (or DMSO for control) at indicated concentrations and 10 μM phosphoramidon (for NEP 24.11 inhibition) (0.5 ml/well). The final DMSO concentration for all experiments was 0.5%. After incubation for 18-24 hours, the medium was collected and centrifuged at 10,000×g for 5 min in order to remove cell debris. The resulting supernatant was used for the measurement of ET-1 by RIA. The ET-1 level from these samples were measured by RIA previously described. Ahn, K., Beningo, K., Olds, G., and Hupe, D. (1992) Proc. Natl. Acad. Sci. USA 89, 8606-10. 
     
                       TABLE IV______________________________________  Example         IC.sub.50 (μM)______________________________________  1       6.6 ± 1.5  3      14.4 ± 1.1______________________________________ 
    
     The compounds of the present invention may be prepared generally as shown in Scheme I. Although Scheme I illustrates the preparation of compounds where A is N, step (a) may also be carried out when A is CH or S(O) n  as defined above. ##STR6## 
     Step (a) involves reacting anthranilic acid derivative of formula (1) with appropriately substituted imidates depicted in formula (2) in ethanol or other hydroxylated solvents at elevated temperatures preferably between 50°-70° C. The reaction is carried out for 8-24 hours preferably 16 to 17 hours. The product, substituted quinazoline 4-one is shown in formula (3) separates as a crystalline solid. The reaction mixture is cooled below room temperature preferably between 0°-5° C. and filtered. The product is washed with water until neutral and air-dried. 
     Step (b) involves reacting quinazoline-4-one depicted in formula (3) with chlorinating agents like phosphorus oxychloride, phosphorus pentachloride or thionyl chloride, preferably phosphorus oxychloride at elevated temperatures preferably at the reflux for periods ranging from 6 to 20 hours preferably 14 to 16 hours. The reaction mixture is cooled to ambient temperatures and poured continuously over crushed ice under vigorous stirring keeping temperatures below 5° C. The solid which separates is filtered and washed with water until neutral. The air-dried solid is extracted with inert solvents like benzene, toluene or xylene preferably toluene and filtered. The filtrate is evaporated in vacuo to give 4-chloro-quinazolines shown in formula (4). 
     Step (c) involves reacting 4-chloro-quinazolines depicted in formula (4) with various primary or secondary amines (1-2 equivalents) in ethereal solvents preferably diethyl ether at temperatures between 15°-25° C. preferably ambient temperature for periods of 16-24 hours preferably 20 hours to give a suspension. The suspension is filtered to give 4-amino quinazolines shown in formula (5) as a solid. In some cases, the reaction mixture is poured in water and the product extracted in ethyl acetate or chloroform, preferably ethyl acetate. The organic extracts are collected and washed with water until excess amine is removed and dried over magnesium sulfate. The solvent is removed under vacuo and 4-aminoquinazolines (5) are isolated by chromatography, preferably silica gel using petroleum ether and ethyl acetate mixture in the ratio of 8:2 to 1:1. 
     Starting anthranilic acids and compounds of formula (2) may be purchased commercially or prepared from commercially available materials by known methods. 
     Schemes II, III and IV illustrate preferred process routes to particular compounds of the present invention. However, these routes may also be generally used to prepare compounds of the present invention with certain limitations. For example, Scheme II shows a preferred route to compounds of the invention in general but where R is trichloromethyl. Scheme III also can be used generally to prepare compounds of the present invention but where R is halo-lower alkyl, in this case, trifluoromethyl. Scheme IV illustrates the preferred route to compounds of Formula III starting with 3-aminopyridine. ##STR7## 
     Scheme V illustrates an alternate route for the synthesis of 2-substituted 4-chloro-quinazoline. 
     Step (a) involves reacting anthranilic acid derivative of Formula (1) with appropriately substituted anhydrides (2), in this case trifluoroacetate anhydride, in the presence of tertiary bases like triethylamine at elevated temperatures preferably at the reflux for 1-6 hours, preferably 2 hours. The volatile components are removed under reduced pressure and the residue treated with an ethereal solvent like diethyl ether and water. The ethereal layer was separated, dried over MgSO 4  and concentrated to give the appropriate benzo d! 1,3!oxazin-4-one derivative as the product. 
     Step (b) involves reacting benzo d! 1,3!oxazin-4-one depicted in Formula 3 with saturated ammonia water at elevated temperatures preferably at 40° C. for 4-8 hours, preferably 5 hours. The reaction mixture is cooled below room temperature preferably between 0°-5° C. and the precipitate obtained, filtered and dried under reduced pressure (0.1-0.5 mm). The product is crystallized from a mixture of petroleum ether and ethyl acetate. 
     Step (c) and step (d) are carried out as described in step (b) and (c) of Scheme I. 
     The compounds of the present invention can be prepared and administered in a wide variety of oral and parenteral dosage forms. Thus, the compounds of the present invention can be administered by injection, that is, intravenously, intramuscularly, intracutaneously, subcutaneously, intraduodenally, or intraperitoneally. Also, the compounds of the present invention can be administered by inhalation, for example, intranasally. Additionally, the compounds of the present invention can be administered transdermally. It will be obvious to those skilled in the art that the following dosage forms may comprise as the active component, either a compound of the present invention, such as a compound of Formula I, II or III or a corresponding pharmaceutically acceptable salt of a compound of Formula I, II or III. 
     For preparing pharmaceutical compositions from the compounds of the present invention, pharmaceutically acceptable carriers can be either solid or liquid. Solid form preparations include powders, tablets, pills, capsules, cachets, suppositories, and dispersible granules. A solid carrier can be one or more substances which may also act as diluents, flavoring agents, binders, preservatives, tablet disintegrating agents, or an encapsulating material. 
     In powders, the carrier is a finely divided solid which is in a mixture with the finely divided active component. 
     In tablets, the active component is mixed with the carrier having the necessary binding properties in suitable proportions and compacted in the shape and size desired. 
     The powders and tablets preferably contain from 5% or 10% to about 70% of the active compound. Suitable carriers are magnesium carbonate, magnesium stearate, talc, sugar, lactose, pectin, dextrin, starch, gelatin, tragacanth, methylcellulose, sodium carboxymethylcellulose, a low melting wax, cocoa butter, and the like. The term &#34;preparation&#34; is intended to include the formulation of the active compound with encapsulating material as a carrier providing a capsule in which the active component with or without other carriers, is surrounded by a carrier, which is thus in association with it. Similarly, cachets and lozenges are included. Tablets, powders, capsules, pills, cachets, and lozenges can be used as solid dosage forms suitable for oral administration. 
     For preparing suppositories, a low melting wax, such as a mixture of fatty acid glycerides or cocoa butter, is first melted and the active component is dispersed homogeneously therein, as by stirring. The molten homogenous mixture is then poured into convenient sized molds, allowed to cool, and thereby to solidify. 
     Liquid form preparations include solutions, suspensions, and emulsions, for example, water or water propylene glycol solutions. For parenteral injection liquid preparations can be formulated in solution in aqueous polyethylene glycol solution. 
     Aqueous solutions suitable for oral use can be prepared by dissolving the active component in water and adding suitable colorants, flavors, stabilizing, and thickening agents as desired. 
     Aqueous suspensions suitable for oral use can be made by dispersing the finely divided active component in water with viscous material, such as natural or synthetic gums, resins, methylcellulose, sodium carboxymethylcellulose, and other well-known suspending agents. 
     Also included are solid form preparations which are intended to be converted, shortly before use, to liquid form preparations for oral administration. Such liquid forms include solutions, suspensions, and emulsions. These preparations may contain, in addition to the active component, colorants, flavors, stabilizers, buffers, artificial and natural sweeteners, dispersants, thickeners, solubilizing agents, and the like. 
     The pharmaceutical preparation is preferably in unit dosage form. In such form the preparation is subdivided into unit doses containing appropriate quantities of the active component. The unit dosage form can be a packaged preparation, the package containing discrete quantities of preparation, such as packeted tablets, capsules, and powders in vials or ampoules. Also, the unit dosage form can be a capsule, tablet, cachet, or lozenge itself, or it can be the appropriate number of any of these in packaged form. 
     The quantity of active component in a unit dose preparation may be varied or adjusted from 0.1 mg to 200 mg preferably 0.5 mg to 100 mg according to the particular application and the potency of the active component. The composition can, if desired, also contain other compatible therapeutic agents. 
     In therapeutic use as inhibitors of endothelin converting enzyme the compounds utilized in the pharmaceutical method of this invention are administered at the initial dosage of about 0.01 mg to about 500 mg/kg daily. A daily dose range of about 0.01 mg to about 100 mg/kg is preferred. The dosages, however, may be varied depending upon the requirements of the patient, the severity of the condition being treated, and the compound being employed. Determination of the proper dosage for a particular situation is within the skill of the art. Generally, treatment is initiated with smaller dosages which are less than the optimum dose of the compound. Thereafter, the dosage is increased by small increments until the optimum effect under the circumstances is reached. For convenience, the total daily dosage may be divided and administered in portions during the day, if desired. 
     The following nonlimiting example illustrates the inventors&#39; preferred methods for preparing the compounds of the invention. 
    
    
     EXAMPLE 1 
     (1-Ethyl-piperidin-3-yl)-(6-iodo-2-trichloromethyl-quinazolin-4-yl)-amine, Monohydrochloride 
     Step 1: Preparation of 6-iodo-2-trichloromethyl-1,2-dihydro-quinazolin-4-one. 
     To a solution of 5-iodoanthranilic acid (131.5 g, 500 mmol) in ethanol (700 mL), 2,2,2-trichloroacetimidate (88.2 g, 500 mmol) was added. The reaction mixture was heated at 45° C. for 3 days under stirring. The solid formed was filtered and washed with fresh ethanol and air-dried. Yield 129.51 g (66.4%). Mp 224°-225° C.  1  H-NMR (DMSO) 7.59 (d, 1h, J=8.6 Hz), 8.21 (dd, 1H, J=2 Hz, J=7.5 Hz), 8.44, 1H, J=1.9 Hz), 13.55 (bs, 1H). MS(CI); M +  =499. CHN calculated for C16H 18  Cl 3  IN 4 .HCl; C: 35.84, H: 3.57, N: 10.45; Found: C: 35.81, H: 3.35, N: 10.44. 
     Step 2: Preparation of 6-iodo-4-chloro-2-trichloromethyl quinazolin. 
     A suspension of 6-iodo-2-trichloromethyl-1,2-dihydro-quinazolin-4-one (38.9 g=100 mmol) in POC1 3  (500 mL) was heated to reflux for 12 hours. The homogeneous solution was cooled and excess POC1 3  was distilled under vacuum. Viscous oil obtained was poured over crushed ice and triturated vigorously to give grey solid, which was dissolved in toluene (200 mL), filtered and evaporated under vacuo to give off-white crystalline solid. Mp 154°-155° C. Elemental Analysis: Calculated for C 9  H 3  Cl 4  IN 2 , C: 26.50, H, 0.74, N: 6.87; Found: C: 26.15, H: 0.79, N. 6.68. 
     Step 3: Preparation of (1-ethyl-piperidin-3-yl)-(6-iodo-2-trichloromethyl-quinazolin-4-yl)-amine, monohydrochloride. 
     6-iodo-4-chloro-2-trichloromethyl-quinazolin (8.14 g, 20 mmol) was dissolved in ether (anhydrous 200 mL) under stirring at rt. To this solution 3-amino-1-ethyl-piperidine (2.56 g, 20 mmol) in ether (anhydrous 30 mL) was added at 0C. The reaction mixture was allowed to warm to rt overnight. Buff colored solid separated which was filtered, washed with ether (200 mL) and air dried. Crude yield: 5.1 g. The crude material was suspended in MeOH and stirred vigorously for 0.5 h and filtered. The solid was dried in vacuo (0.01 mm). Yield: 3.72 g, (34.7%). Mp 265°-266° C. 
     In a process analogous to Example 1 using appropriate starting materials, the corresponding compounds of Formula I are prepared as follows: 
     EXAMPLE 2 
     (1-Ethyl-piperidin-3-yl)-(6-iodo-2-phenyl-quinazolin-4-yl)-amine. MS (CI) M+1=459, CHN calculated for C 21  H 23  IN 4  ; C: 55.03; H: 5.06; N: 12.22; Found: C: 54.99; H: 5.11, N: 11.82. 
     EXAMPLE 3 
     (1-Ethyl-piperidin-3-yl)-(6-chloro-2-trichloromethyl-quinazolin-4-yl)-amine. Mp 274°-276° C., CHN calculated for C 16  H 18  Cl 4  N 4 .HCl, C: 43.22, H: 4.30, N: 12.00; Found: C: 43-23, H: 4.16 N: 12.47. 
     EXAMPLE 4 
     (1-Ethyl-piperidin-3-yl)-(6-nitro-2-trichloromethyl-quinazolin-4-yl)-amine. MS (CI) M+1=418. CHN calculated for C 14  H 18  Cl 3  N 5  O 2 .HCl; C: 42.22, H: 4.21, N: 15.39, Found: C: 42.30; H: 4.19, N: 15.01. 
     EXAMPLE 5 
     (2-tert-Butyl-6-iodo-quinazolin-4-yl)-(1-ethyl-piperidin-3-yl)-amine, calculated for C 19  H 27  IN 4 . 
     EXAMPLE 6 
     N-(6-Iodo-2-trichloromethyl-quinazolin-4-yl)-ethane-1,2-diamine hydrochloride, MS (CI) M+1 36.5=431. 
     EXAMPLE 7 
     N-(6-Iodo-2-trichloromethyl-quinazolin-4-yl)-N 1  -methyl-ethane-1,2-diamine. MS (CI) M+1=444. 
     EXAMPLE 8 
     N-(6-Iodo-2-trichloromethyl-quinazolin-4-yl)-N 1 ,N 1  -dimethyl-ethane-1,2-diamine. MS (CI) M+1=459. 
     EXAMPLE 9 
     (6-Iodo-2-trichloromethyl-quinazolin-4-yl -(2-piperidin-1-yl-ethyl)-amine, mp 254°-255° C. (dec), MS (CI): m/z 499 (MH) + . 
     EXAMPLE 10 
     (6-Iodo-2-trichloromethyl-quinazolin-4-yl)-(2-morpholin-4-yl-ethyl)-amine, mp 182°-183° C. (dec), MS(CI): m/z 501 (MH) + . 
     EXAMPLE 11 
     (1-Ethyl-pyrrolidin-2-yl -methyl)-(6-iodo-2-trichloromethyl-quinazolin-4-yl)-amine, mp 147°-153° C., MS (CI): m/z 499 (MH) + . 
     EXAMPLE 12 
     (1 -Aza-bicyclo 2,2,2,!oct-3-yl)-(6-iodo-2-trichloromethyl-quinazolin-4-yl)-amine, mp &gt;280° C. (dec), MS (CI): m/z 497 (MH) + . 
     EXAMPLE 13 
     N-(7-Chloro-2-trichloromethyl-quinazolin-4-yl)-N&#39;,N&#39;-diisopropyl-ethane-1,2-diamine. mp 199°-203° C. Elemental analysis calc&#39;d for C 17  H 22  N 4  Cl 5 .HCl: C: 44.33; H: 5.3; N: 12.16; Found C: 44.34; H: 5.30; N: 12.26. 
     EXAMPLE 14 
      3-(6-Iodo-2-trichloromethyl-quinazolin-4-yl-amino)-piperidin-1-yl!-acetic acid potassium salt. Elemental analysis calc&#39;d for C 16  H 15  N 4  O 2  Cl 3  IK: C: 33.83; H: 2.64; N: 9.86 Found C: 33.68; H: 3.01; N: 9.72. 
     EXAMPLE 15 
     (1-Aza-bicyclo 2.2.2!oct-3-yl)-(6-iodo-2-trichloromethyl-quinazolin-4-yl)-amine monohydrochloride, mp &gt;280° C. (dec), MS(CI): M+1=498. 
     EXAMPLE 16 
     N&#39;-(6-Iodo-2-trichloromethyl-quinazolin-4-yl)-N,N,N&#34;,N&#34;-tetramethyl-propane-1,2,3-triamine monohydrochloride, mp 207°-208° C. (dec), MS(CI): M+1=517. 
     EXAMPLE 17 
     (1-Ethyl-piperidin-3-yl)-(6-iodo-2-trifluoromethyl-quinazolin-4-yl)-amine 
     Step 1: 6-iodo-2-trifluoromethyl-benzo d! 1,3!oxazin-4-one. 
     5-iodo-2-aminobenzoic acid (2.1 g, 8 mmole) was mixed with trifluoroacetic anhydride (12 g, 57 mmole) and 2 mL of triethyl amine, heated to reflux for 2 h. The solvent was removed under reduced pressure, the residue was stirred with 25 mL of ether and 5 mL of water. The organic layer was separated, dried and concentrated to give 1.92 g of product, mp 131°-132° C., MS (CI): m/z 342 (MH) + . 
     Step 2: 6-iodo-2-trifluoromethyl-3H-quinazolin-4-one. 
     6-iodo-2-trifluoromethyl-benzo d! 1,3!oxazin-4-one (0.6 g, 1.76 mmole) was stirred with 25 mL of concentrated ammonia water at 40° C. for 5 h, cooled to 0C, the precipitate was filtered and dried under vacuo. The product was recrystallized from ethyl acetate and haxanes to give 0.58 g, mp &gt;255° C. (sub), MS (CI) m/z 341 (MH) + . 
     Step 3: 6-iodo-2-trifluoromethyl-4-chloroquinazoline. 
     6-iodo-2-trifluoromethyl-3H-quinazolin-4-one (3.1 g, 9.1 mmole) was mixed with 20 mL of POC1 3 , heated to reflux for 3 h, removed most of unreacted POC1 3  under vacuo. The residue was extracted with 15 mL of NaHCO 3  (sat) and 200 mL of ether, ether layer was dried with MgSO 4  and concentrated to give the light yellow solid 3.05 g, mp 145°-146° C., MS (CI): m/z 359 (MH) + . 
     Step 4: (1-ethyl-piperidin-3-yl)-(6-iodo-2-trifluoromethyl-quinazolin-4-yl)-amine. 
     6-iodo-2-trifluoromethyl-4-chloroquinazoline (1.5 g, 4.2 mmole) was mixed with 3-amino-ethyl piperidine (0.62 g, 4.8 mmole) and triethyl amine in 200 mL of ether. The product was isolated as hydrochloride salt by previous method, to give 1.25 g, mp 296°-297° C. (dec), MS (CI): m/z 359 (MH) + .