I. C. Ivanov, S. K. Karagiosov, M. F. Simeonov: A Facile Synthesis of
[1]Benzopyrano[4,3-b]pyridin-5-ones. - Liebigs Ann. Chem. 1992, 203-207.

D. Heber, I. C. Ivanov, S. K. Karagiosov: The Vilsmeier Reaction in the Synthesis of 3-Substituted [1]Benzopyrano [4,3-b]pyridine-5-ones.
An Unusual Pyridine Ring Closure. - J. Heterocycl. Chem., 1995, 32, 505-509.

I. C. Ivanov, S. K. Karagiosov: Two Methods for the Preparation of
3-Dialkylaminomethyl Derivatives (Mannich Bases) of 4-Aminocoumarin: A New Type of Intramolecular Hydride Transfer. - Synthesis 1995, No. 6, 633-634.

I. C. Ivanov, E. V. Stoyanov, P. S. Denkova, V. S. Dimitrov: Synthesis of Substituted 2-Dihydro-2-imino-7-methyl-1,6(6H)-naphthyridin-5-ones. - Liebigs Ann. Chem. 1997, 1977-1981.

E. V. Stoyanov, I. C. Ivanov: Synthesis of Some Substituted 2H-Pyrano[3,2-c]pyridine-2,5(6H)-diones. Reaction of Their 3-Acetyl Derivatives with Methyl 3-Amino-2-butenoate. - Synth. Commun. 1998, 28 (10), 1755-1767.

W. Kantlehner, M. Vettel, H. Lehmann, K. Edelmann, R. Stieglitz, I. C. Ivanov: Orthoamide LI. Push-Pull-Butadiene und Heterocyclen aus CH₂-aciden Verbindungen und Orthoamiden von Alkincarbonsäuren. - J. Prakt. Chem. / Chem. Ztg. 1998, 340, 408-423.

E. V. Stoyanov, I. C. Ivanov, D. Heber: General Method for the Preparation of Substituted 2-Amino-4H,5H-pyrano[4,3-b]pyran-5-ones and 2-Amino-4H-pyrano[3,2-c]pyridine-5-ones. - Molecules 2000, 5, 19-32.

Willi Kantlehner, Erwin Haug, Willy Kinzy, Oliver Scherr, Ivo C. Ivanov: Die Synthese von 2-Methyl-5-phenacyl-1,3,4-thiadiazolen. - Z. Naturforsch. 2004, 59b, 366 – 374.

Erwin Haug, Willi Kantlehner (Hochschule Aalen), Ivo Christov Ivanov (Medical University of Sofia), Dirk Bruns, Björn Sievers: Conference Paper: "Triacetamid – ein neues Acetylierungsmittel für Aromaten? (in German)", Mini-Iminiumsalz-Tagung (Mini-ImSaT) Siegmundsburg, Germany 2004 (free PDF on demand); https://www.researchgate.net/publication/317932470_Triacetamid_-_ein_neues_Acetylierungsmittel_fur_Aromaten_in_German

Lyubomir D. Raev, Wolfgang Frey, Ivo C. Ivanov: Coumarin-enaminoester adducts: Structure corrections (X-ray) and some novel transformations. Synthesis of annulated tricyclic 2-pyridones. - Synlett 2004 (9), 1584-1588.

Edmont V. Stoyanov, Ivo C. Ivanov: Convenient replacement of the hydroxy by an amino Group in 4-hydroxycoumarin and 4-hydroxy-6-methyl-2-pyrone under microwave Irradiation. - Molecules 2004, 9, 627–631.

W. Kantlehner, E. Haug, J. Mezger, R. Kreß, G. Ziegler, B. Sievers, I. C. Ivanov, S. Leonhardt: Und sie geht doch! – Die Lehrbücher müssen umgeschrieben werden. Neuere Anschauungen zum Verlauf der Fries’schen Verschiebung. - Horizonte 2005, 26, 48-53 (free PDF file).

Ivo C. Ivanov, Toma N. Glasnov, Dieter Heber: Synthesis of 2H-chromeno-[4,3-b]pyridine-2,5(1H)-diones and related heterocycles via the Erlenmeyer-Ploechl reaction. - J. Heterocyclic Chem., 2005, 42 (5), 857-861.

Imran Ali Hashmi, Wolfgang Frey, Ivo C. Ivanov, Willi Kantlehner: One-pot, Three-component Synthesis of 7H-[1,3,4]Thiadiazolo[3,2-a]pyridines from 2-Phenacyl-[1,3,4]thiadiazole Derivatives and Arylmethylene-cyanoacetic Acid Derivatives. - Z. Naturforsch. 2007, 62b, 1298–1304.

Ivo C. Ivanov, Toma N. Glasnov, F. Belaj: tert-Amino effect at a coumarin and a 2-quinolone system: Synthesis of 1,2 fused 5H-chromeno[4,3-b]pyridin-5-ones and a 6H-benzo[h][1,6]naphthyridin-5-one. - J. Heterocyclic Chem. 2008, 45, 177-180.

Toma N. Glasnov, Ivo C. Ivanov: A convenient approach to the synthesis of dialkyl 5-oxo-1,2-dihydro-5H-chromeno[4,3-b]pyridine-2,3-dicarboxylates. - Synth. Commun., 2008, 38 (10), 1579-1588.

W. Kantlehner, J. Mezger, R. Kreß, H. Hartmann, T. Moschnya, I. Tiritiris, B. Iliev, O. Scherr, G. Ziegler, B. Souley, W. Frey, I. C. Ivanov, M. G. Bogdanov, U. Jäger, G. Dospil, T. Viefhaus: Orthoamide, LXIX. Beiträge zur Synthese N,N,N',N',N",N"-peralkylierter Guanidine und N,N,N',N',N",N"-persubstituierter Guanidiniumsalze. - Z. Naturforsch. 2010, 65b, 873–906.

Willi Kantlehner, Ivo C. Ivanov, Ioannis Tiritiris: Orthoamides and Iminium Salts, LXXV. Contribution to the Formation of 2-Formyl-1,1,3,3-tetramethylguanidine and the Isomeric 1,1-Dimethyl-3-dimethylamino-methylene-urea - Z. Naturforsch. 2012, 67b, 331–336.

Ivo C. Ivanov, Violina T. Angelova, Nikolay Vassilev, Ioannis Tiritiris, Boyan Iliev: Synthesis of 4-Aminocoumarin Derivatives with N-Substituents Containing Hydroxy or Amino Groups - Z. Naturforsch. 2013, 68b, 1031–1040 / DOI: 10.5560/ZNB.2013-3102.

Ivo C. Ivanov, Violina T. Angelova, Ioannis Tiritiris, Toma Glasnov: Unexpected Synthesis of a 5H-chromeno[3,4-c]pyridine Derivative from 4-Chlorocoumarin-3-carbaldehyde and Malononitrile - J. Heterocyclic Chem. 2014, 51, 1031-1035; DOI: 10.1002/jhet.2103.

Willi Kantlehner, Georg Ziegler, Oliver Scherr, Michael Csiesielski, Alain Goeppert, Markus Wezstein, Jochen Mezger, Ivo C. Ivanov, Sylvia Leonhardt: Orthoamide und Iminiumsalze, LXXXIV. Die Synthese von starken Formylierungsmitteln im präparativen Großmaßstab: Tris(dichlormethyl)amin - Z. Naturforsch. 2014, 69b, 525 – 532 / DOI: 10.5560/ZNB.2014-3270.

Willi Kantlehner, Jochen Mezger, Ivo C. Ivanov: Orthoamide und Iminiumsalze, LXXXVII. Eine neue, einfache Synthese für 1,3-Dimethylthymin - Z. Naturforsch. 2014, 69b, 519 – 524 / DOI: 10.5560/ZNB.2014-4053.

Violina T. Angelova, Wolfgang Frey, Ivo C. Ivanov, Nikolay Vassilev, Toma N. Glasnov: One-pot synthesis of a chromeno[4,3,2-de]-1,6-naphthyridine derivative from 4-chlorocoumarin-3-carbaldehyde - Bulg. Chem. Commun. (Special Issue A)  2014, 46, 53–58.

Lyubomir D. Raev, Ivo C. Ivanov, Henri A. Astroug, Wolfgang Frey, Silvia G. Agontseva: Synthesis of some 6-alkylureido-4-aryl-2(1H)-pyridones: further transformations and pharmacological activity. - Z. Naturforsch. 2015, 70b / DOI 10.1515/ZNB-2015-0066

Ivo C. Ivanov: A Centenary of the Birth of Professor Christo Ivanov. - Chemistry: Bulgarian Journal of Science Education 2016, 25 (2), 230-266. (PDF file)

Lyubomir D. Raev, Ivo C. Ivanov, Silvia G. Agontseva: Addition of some 6-amino-4-aryl-2(1H)-pyridones to phenylisocyanate and related reactions. - Z. Naturforsch. 2019, 74b (2). Published Online: 2019-01-26 | DOI: https://doi.org/10.1515/znb-2018-0184

Willi Kantlehner, Georg Ziegler, Jochen Mezger, Jean Sommer, Benoit Louis, Björn Sievers, Ivo C. Ivanov, Xavier Samain, Silvia Leonhardt, Wolfgang Frey: Zur Formylierung von Hydroxy- und Alkoxyaromaten mit Ameisensäure - Z. Naturforsch. 2019, 74b.  Published Online: 2019-09-28 | DOI: https://doi.org/10.1515/znb-2019-0076.

Nikolay G. Vassilev and Ivo C. Ivanov, A Small Change in Structure, a Big Change in Flexibility, Molecules 2023, 28, 8004. Published Online: 8 December 2023 | DOI:
https://doi.org/10.3390/molecules28248004